Board Game Arena - User contributions [en]

Tips hadron

2024-08-29T19:33:38Z

Shinuito: /* Endgame */

Hadron is a drawless two-player game where you win by playing the last move. In Hadron, in every board position, both players always have the same set of legal moves. This means that the game will always come down to the last move and you can't necessarily win by claiming points or areas in games like Amazons or Go etc.

However, there are ways to gain advantages on the board, similar to claiming areas and points in other games. You can create small areas of the board where you are guaranteed to have the last move, and these behave like an advantage or points in some ways.

There are also small areas where either player can get the last move by moving first.

Let's look at some common positions that appear in the late stages of a Hadron game to get a feeling for who might be winning in the overall position. We can also look at how the overall situation changes as these positions combine together. We can also look at how to create or destroy such positions to form an early-game strategy.

=== Endgame ===

In Hadron it can often be the case, that near the end of the game, the board splits up into disconnected parts that no longer affect each other. Assume that in the given examples, no new moves can be created outside the area where there is a legal move to begin with.

==== Stars or Parity ====

The simplest of these are areas where only one move is left available to either player and no new moves are created afterward. For simplicity lets call these kinds of moves '''stars'''. This can happen when the point is completely surrounded in the center of the board or in the corner but also in other situations. Some examples are shown below. Note: This is not an exhaustive list.

[[File:star_1.png]] [[File:star_2.png]] [[File:star_3.png]] [[File:star_4.png]]

If these are the only types of moves left to play on the board, then the winner is determined by simply counting the available moves left. On '''your''' turn you want there to be an '''odd''' number of stars left, while on the '''opponent's''' turn you want there to be an '''even''' number. This way you will guarantee yourself the last move. Since you want to play last, you need there to be 1, 3, 5 etc moves left, while you want there to be 0, 2, 4 moves etc for your opponent left. Some players call this evenness or oddness the '''parity''' of the game.

A '''good''' parity for you is '''odd''' on your turn, '''even''' on your opponent's turn.

Mentally you can cancel off pairs of these points since it's only where there is an even or odd number left that matters. You can think of it like +1 for the player to move if there's an odd number, or 0 if there's an even number.

==== Corridors ====

It can happen that on part of the board one player can always guarantee themselves the last move, in some cases letting the opponent play multiple moves in a row while playing elsewhere. Abstractly it makes sense to call them corridors because in a special case they can look like a straight line of empty points.

For example in the image below which is at the edge of the board, Blue can always play the last move in this area. They can play first and it will be the last move, or they can let Red play either 1 or 2 moves here and still get the last move.

[[File:corridor_1.png]]

Example corridors on a 5x5 board:

[[File:corridor_2.png]]
This is like a +1 to Blue as Blue can always play the last move here, playing first or second.

[[File:corridor_3.png]]
This is like a +2 to Blue as Blue can let Red play twice in a row and still get the last move here.

[[File:corridor_4.png]]
This is like a +3 to Blue as Blue can let Red play three times in a row and still get the last move here.

A useful thing about the corridors is that they are a way for you to control the parity of the game. If the parity is good, then you don't need to change it. If the parity is bad, then you can play in your corridor to '''close''' it and give the opponent the bad parity, that is play the last move in the corridor area.

==== Corridor plus stars ====
In a game where there is only a corridor left and one (odd) or two (even) number of stars, there is a winning strategy.

In the '''even''' case, on your turn the parity (even) is bad for you, so you should '''close''' the corridor and give the opponent the bad parity.

In the odd case, on your turn the parity (odd) is good for you, so you should play one of the stars leaving bad parity (even) for the opponent. If your opponent plays the corridor you can answer and '''close''' the corridor and the parity is bad for the opponent. If your opponent also plays a star, since there was an odd number you can keep repeating this step.

=== Early Game ===

(to be added)

File:Corridor 4.png

2024-08-29T19:17:18Z

Shinuito: A four space corridor for Blue in Hadron

== Summary ==
A four space corridor for Blue in Hadron

File:Corridor 3.png

2024-08-29T19:16:53Z

Shinuito: A three space corridor for Blue in Hadron

== Summary ==
A three space corridor for Blue in Hadron

File:Corridor 2.png

2024-08-29T19:16:27Z

Shinuito: A two space corridor for Blue in Hadron

== Summary ==
A two space corridor for Blue in Hadron

File:Corridor 1.png

2024-08-29T19:10:18Z

Shinuito: Blue has the advantage in this corridor.

== Summary ==
Blue has the advantage in this corridor.

File:Star 4.png

2024-08-29T18:39:26Z

Shinuito: A single point either player can play in Hadron.

== Summary ==
A single point either player can play in Hadron.

File:Star 3.png

2024-08-29T18:39:09Z

Shinuito: A single point either player can play in Hadron.

== Summary ==
A single point either player can play in Hadron.

File:Star 2.png

2024-08-29T18:38:55Z

Shinuito: A single point either player can play in Hadron.

== Summary ==
A single point either player can play in Hadron.

File:Star 1.png

2024-08-29T18:38:39Z

Shinuito: A single point either player can play in Hadron.

== Summary ==
A single point either player can play in Hadron.

Tips hadron

2024-08-28T17:41:16Z

Shinuito: Beginning template for a Hadron strategy tips section. Helpful to have a template for collaboration.

Tips meridians

2023-09-12T12:44:16Z

Shinuito: /* Tempo */ -> adding in ideas to sacrifice pieces.

Meridians is an annihilation game where you have to capture all of your opponents stones. In some games you will be able to actively capture your opponents pieces, but in others it might be that you have to wait until your opponent captures themselves. Since there is no passing in meridians, the board will continue to fill up, and somebody as a result will lose all of their pieces.

Meridians strategy is still evolving but I'll try to capture some key ideas that should help you to come up with your own strategies for winning games.

=== Capturing pieces ===

Since the game is about annihilation, it's important to know how to capture pieces. Stones and groups of stones are alive when they have a straight line '''path''' to another separate stone or group. In order to capture the opponents groups you should break these paths by interrupting them with your own pieces.

Now it might seem that even when you interrupt a path the opponent will just place a new stone to create a new path, saving the attacked stones, but this is not always going to be possible. Here's some examples of that below:

[[File:Meridians_capture_1.png]]

In the example above, it showcases two ideas for capturing pieces.

==== minimum space ====

The first is that groups need a certain minimum amount of space in order to avoid being captured. You need enough room to be able to fit two stones or two groups separated by a one space gap in order to have a path between them. In this example, Black's pieces were all along the second line (one step away from the edge) which left Black no room to make a path to a new stone.

Here's another example of a stone being captured in the center of the board

[[File:Meridians_capture_center.png]]

==== double attack ====

While it's true that the opponent can always try to add another stone to make a path and save attacked stones, this requires that the new stone see both of the attacked stones, that is there are two paths joining to both attacked groups that cross at one intersection, which is where you place the new stone. This won't always be the case, and so the opponent will have to decide to save one group or the other and won't be able to save both.

Here's one more example of that kind of double attack below:

[[File:Meridians_capture_2.png]]

There's no way for White to find a place to play a new stone which has a path to both groups of two stones. So white will have to choose to save one or the other.

=== Territory and living groups ===

Since it can be the case that you won't be able to capture all of your opponents groups and you can't pass, it makes sense to be able to reserve spaces to play for yourself which your opponent can't play for later in the game. It makes sense to define territory as moves that can only be played by one colour.

In the example below Black has territory in the bottom right marked blue, while white has some small territories in the top left, one of which is marked in orange. In order to count the sizes of these territories it makes sense to only count moves that a player can play which doesn't capture their group. So for Black, though there is 11 free spaces, at most 8 of them can be played. The dashed three points around the single stone shouldn't be played, in order to play the other 8 moves. This is best Black can do.

[[File:Meridians_territory.png]]

In the upper right area in the above example, rather than having a stone on the corner of the board, white has a stone on the side, and so needs to reserve the neighbouring 4 spaces in order to not have their group be captured (assuming all other territories are to be filled in completely). So even though there is 7 empty spaces in this orange area, White will only fill in three of these spots, excluding the four dashed ones.

==== Efficiency of filling in territory ====
The most efficient place to play a path stone is in the corner as seen above, since one only needs to reserve three spaces for the groups not to merge and be captured. A path stone on the edge requires four reserved spaces, and a stone in the centre requires all six spaces around it to be reserved, if this is the only path keeping a surrounding group alive.

==== Living groups ====

In the previous example of territory, both the Black and White group are alive and cannot be captured by the opponent. They both have a single stone in a territory, meaning the opponent has no legal moves there and so cannot threaten or make any moves to capture the opponents groups.

This is not the only way to make a living group however. Earlier in the game, White surrounded some Black stones, and placed a single path stone in this area, see below. The way for black to capture the single stone and the whole group would involve black playing at the marked X point. However because of the way capturing works in Meridians compared to some other similar games, if Black plays the X, they first remove their own captured stones, before giving the opponent a turn to save any stones with no paths. So Black playing the X, joins their two groups, capturing them, and actually making the area into territory for White instead.

[[File:Meridians_alive.png]]

This is kind of a seki, if you're familiar with the term from the board game Go. The X is a point that neither player wishes to play as it is bad for both, and so both the large white group, and the two black groups can live in this area, as long as white does not find another area to create a path in. Both players also still have moves in this area, so it's a shared area, as opposed to a territory for one or the other.

==== Taking the most points with living groups ====

Once you have a living group, the best way usually of making points is to create a territory, ideally with a path stone on the corner of the board, but the side is also fine. Having a path stone in a territory means, if you surround any other small areas with opponents groups, you can also capture these. In the previous example White's main group was alive, because neither player wanted to play the X point, but later when White created a territory, White could come back to play moves like the X move, and capture the black stones.

Generally however if you surround multiple areas containing the opponents stones, and you can't create a territory with room for a path stone, you should capture the opponents stones which leave you with the more territory. That is leave the opponents stones alive in the smallest area, and capture all other stones. Each capture-able opponent stone will be like one point of territory when it is removed, so you can use this a guideline for a minimum amount of points in an area.

=== Efficiency, double paths and Tempo ===

So while general strategies are still being worked on, I'll just mention a few ideas that should be useful in playing the game, picking strategies and where to play moves.

==== Efficiency ====

Like in many other games, in the opening you typically want your moves to be efficient. If they can do two things at once, they can often be better than a single purpose move. If a move can create a path for a group while also threatening an opponents groups, it could be sometimes better than playing just a path more defensively. Other times it could be better to prepare a defensive move before creating a stronger attack, but that can be covered in the section on tempo.

- So moves that can attack and defend at the same time, or a move that can enlarge the area you surround while making the opponents area smaller, or threatening to invade their area could be good candidates for efficient moves.

- An efficient way to make points is also to create territories, and since your opponent can only play places their stones can "see" or be in line with, blocking off an area from the opponents line of sight can be an efficient way to create points.

- A way to remove points from the opponent is to have stones in their area before they can make a territory. Even if the stones get captured ultimately, you can possibly, in the best case, halve the number of points in an area, if both players are forced to play there at the end of the game. So sealing an area off from the opponent to create a territory could be worth twice as much potentially as letting the opponents stones invade.

- It might be efficient to play with fewer groups on smaller boards, since the less groups you have the less points you have to reserve for each group to stay alive. Equally the less groups you have and few path stones, the more you can connect you groups and focus on the cutting the opponents groups.

==== Double paths ====

Since every group needs a path to another group or stone not to be captured, it's important to create these, possibly in efficient ways as mentioned in the previous section. Another idea is to consider placing a path stone in such a way that it is harder for the opponent to cut it, or that it gives you more time to defend if they try to cut it.

[[File:Meridians_double_path.png]]

For example in this game above, the last white move creates a double path to the main white group. That is there is two lines of sight between the last placed stone and the main group. In this particular situation, though it can be cut it takes two moves to do so, which give white time to do other things, like counter attacking the black stones in this area, or separating the two white stones on the bottom and so on.

So double paths are stronger in that they give you more time, an additional move, to respond to a cutting threat.

==== Tempo ====

In meridians and other games, it's useful to play moves that give you initiative. Sometimes this is called gaining a tempo, or if you have to spend one more move defending, or unnecessarily play a move or defensive move, it can be seen as losing a tempo or giving initiative to the opponent to play where they want to.

In the previous section example, White gave up the initiative when playing a double path move. However when Black next tries to cut this double path, which we said takes moves to do, they end up losing a tempo when white counter cuts like below, as now Black is on the defensive to save one of their stones.

[[File:Meridians_crosscut.png]]

Another potentially useful term when it comes to tempo is the idea of a shape that we can call a '''cross cut'''. Highlighted in the previous image, are two groups of each color that both have paths though a single intersection. This happens often enough in Meridians that it might be useful to give it a name. It was also seen previously in the section on living groups, with the group living in seki creating a cross cut.

The player that can gain an extra path for one of the groups involved in the cross cut will be at an advantage, as they will be able to connect through the cross cut first cutting the opponents groups. In some cases this connecting move gains a tempo putting the opponent on the back foot, taking initiative.

You can see in the same example above that White's large group is involved in two cross cuts, and even if they could be cut across one, they would still be safe because of the other existing. Black needs to find a way to gain paths for all groups in these cross cuts to have any reasonable chance attack White's main group, and so creating one of more of these cross cuts can be a tactic to take and hold initiative, or to outright live as in the case of the seki previously.

One other idea is to sacrifice to gain a tempo. That is, you might not need to save every piece on the board. If you find yourself forced into defending all game, you can try to figure out which stones are important and which ones are not, and then sacrifice some of them to either counter attack or to seal off or break into a larger area. This could include some of the pie stones for instance mentioned in the next section on the pie rule.
=== The Pie rule ===

One other thing, if you're playing in Arena or just generally, is that there is a pie rule in place for balance. Before the pie rule, the White player could just play in the center, and combining that with moving first gave them an advantage it was found. With the pie rule you place one stone of each color and give the opponent the option of choosing which colour to play as.

What this means is that a) you should place stones where you think you would be happy to play as either colour, remembering White gets the first move and b) you should possibly try to balance out the first move advantage white has, by giving them a "worse" opening position, whatever that means. A guess at this might be giving white worse access to the center, either out of line with central areas, or giving Black the chance to counter attack. So possibly a white stone nearing the edge vs a black stone nearing but not exactly in the center could be balanced but it will probably depend on the specifics exactly.

It could be useful to review some Arena games, or tournament games that use the pie rule to see what some other players are trying out, but of course experiment yourself too!

Tips meridians

2023-09-12T12:40:43Z

Shinuito: Initial ideas for meridians strategy

Meridians is an annihilation game where you have to capture all of your opponents stones. In some games you will be able to actively capture your opponents pieces, but in others it might be that you have to wait until your opponent captures themselves. Since there is no passing in meridians, the board will continue to fill up, and somebody as a result will lose all of their pieces.

Meridians strategy is still evolving but I'll try to capture some key ideas that should help you to come up with your own strategies for winning games.

=== Capturing pieces ===

Since the game is about annihilation, it's important to know how to capture pieces. Stones and groups of stones are alive when they have a straight line '''path''' to another separate stone or group. In order to capture the opponents groups you should break these paths by interrupting them with your own pieces.

Now it might seem that even when you interrupt a path the opponent will just place a new stone to create a new path, saving the attacked stones, but this is not always going to be possible. Here's some examples of that below:

[[File:Meridians_capture_1.png]]

In the example above, it showcases two ideas for capturing pieces.

==== minimum space ====

The first is that groups need a certain minimum amount of space in order to avoid being captured. You need enough room to be able to fit two stones or two groups separated by a one space gap in order to have a path between them. In this example, Black's pieces were all along the second line (one step away from the edge) which left Black no room to make a path to a new stone.

Here's another example of a stone being captured in the center of the board

[[File:Meridians_capture_center.png]]

==== double attack ====

While it's true that the opponent can always try to add another stone to make a path and save attacked stones, this requires that the new stone see both of the attacked stones, that is there are two paths joining to both attacked groups that cross at one intersection, which is where you place the new stone. This won't always be the case, and so the opponent will have to decide to save one group or the other and won't be able to save both.

Here's one more example of that kind of double attack below:

[[File:Meridians_capture_2.png]]

There's no way for White to find a place to play a new stone which has a path to both groups of two stones. So white will have to choose to save one or the other.

=== Territory and living groups ===

Since it can be the case that you won't be able to capture all of your opponents groups and you can't pass, it makes sense to be able to reserve spaces to play for yourself which your opponent can't play for later in the game. It makes sense to define territory as moves that can only be played by one colour.

In the example below Black has territory in the bottom right marked blue, while white has some small territories in the top left, one of which is marked in orange. In order to count the sizes of these territories it makes sense to only count moves that a player can play which doesn't capture their group. So for Black, though there is 11 free spaces, at most 8 of them can be played. The dashed three points around the single stone shouldn't be played, in order to play the other 8 moves. This is best Black can do.

[[File:Meridians_territory.png]]

In the upper right area in the above example, rather than having a stone on the corner of the board, white has a stone on the side, and so needs to reserve the neighbouring 4 spaces in order to not have their group be captured (assuming all other territories are to be filled in completely). So even though there is 7 empty spaces in this orange area, White will only fill in three of these spots, excluding the four dashed ones.

==== Efficiency of filling in territory ====
The most efficient place to play a path stone is in the corner as seen above, since one only needs to reserve three spaces for the groups not to merge and be captured. A path stone on the edge requires four reserved spaces, and a stone in the centre requires all six spaces around it to be reserved, if this is the only path keeping a surrounding group alive.

==== Living groups ====

In the previous example of territory, both the Black and White group are alive and cannot be captured by the opponent. They both have a single stone in a territory, meaning the opponent has no legal moves there and so cannot threaten or make any moves to capture the opponents groups.

This is not the only way to make a living group however. Earlier in the game, White surrounded some Black stones, and placed a single path stone in this area, see below. The way for black to capture the single stone and the whole group would involve black playing at the marked X point. However because of the way capturing works in Meridians compared to some other similar games, if Black plays the X, they first remove their own captured stones, before giving the opponent a turn to save any stones with no paths. So Black playing the X, joins their two groups, capturing them, and actually making the area into territory for White instead.

[[File:Meridians_alive.png]]

This is kind of a seki, if you're familiar with the term from the board game Go. The X is a point that neither player wishes to play as it is bad for both, and so both the large white group, and the two black groups can live in this area, as long as white does not find another area to create a path in. Both players also still have moves in this area, so it's a shared area, as opposed to a territory for one or the other.

==== Taking the most points with living groups ====

Once you have a living group, the best way usually of making points is to create a territory, ideally with a path stone on the corner of the board, but the side is also fine. Having a path stone in a territory means, if you surround any other small areas with opponents groups, you can also capture these. In the previous example White's main group was alive, because neither player wanted to play the X point, but later when White created a territory, White could come back to play moves like the X move, and capture the black stones.

Generally however if you surround multiple areas containing the opponents stones, and you can't create a territory with room for a path stone, you should capture the opponents stones which leave you with the more territory. That is leave the opponents stones alive in the smallest area, and capture all other stones. Each capture-able opponent stone will be like one point of territory when it is removed, so you can use this a guideline for a minimum amount of points in an area.

=== Efficiency, double paths and Tempo ===

So while general strategies are still being worked on, I'll just mention a few ideas that should be useful in playing the game, picking strategies and where to play moves.

==== Efficiency ====

Like in many other games, in the opening you typically want your moves to be efficient. If they can do two things at once, they can often be better than a single purpose move. If a move can create a path for a group while also threatening an opponents groups, it could be sometimes better than playing just a path more defensively. Other times it could be better to prepare a defensive move before creating a stronger attack, but that can be covered in the section on tempo.

- So moves that can attack and defend at the same time, or a move that can enlarge the area you surround while making the opponents area smaller, or threatening to invade their area could be good candidates for efficient moves.

- An efficient way to make points is also to create territories, and since your opponent can only play places their stones can "see" or be in line with, blocking off an area from the opponents line of sight can be an efficient way to create points.

- A way to remove points from the opponent is to have stones in their area before they can make a territory. Even if the stones get captured ultimately, you can possibly, in the best case, halve the number of points in an area, if both players are forced to play there at the end of the game. So sealing an area off from the opponent to create a territory could be worth twice as much potentially as letting the opponents stones invade.

- It might be efficient to play with fewer groups on smaller boards, since the less groups you have the less points you have to reserve for each group to stay alive. Equally the less groups you have and few path stones, the more you can connect you groups and focus on the cutting the opponents groups.

==== Double paths ====

Since every group needs a path to another group or stone not to be captured, it's important to create these, possibly in efficient ways as mentioned in the previous section. Another idea is to consider placing a path stone in such a way that it is harder for the opponent to cut it, or that it gives you more time to defend if they try to cut it.

[[File:Meridians_double_path.png]]

For example in this game above, the last white move creates a double path to the main white group. That is there is two lines of sight between the last placed stone and the main group. In this particular situation, though it can be cut it takes two moves to do so, which give white time to do other things, like counter attacking the black stones in this area, or separating the two white stones on the bottom and so on.

So double paths are stronger in that they give you more time, an additional move, to respond to a cutting threat.

==== Tempo ====

In meridians and other games, it's useful to play moves that give you initiative. Sometimes this is called gaining a tempo, or if you have to spend one more move defending, or unnecessarily play a move or defensive move, it can be seen as losing a tempo or giving initiative to the opponent to play where they want to.

In the previous section example, White gave up the initiative when playing a double path move. However when Black next tries to cut this double path, which we said takes moves to do, they end up losing a tempo when white counter cuts like below, as now Black is on the defensive to save one of their stones.

[[File:Meridians_crosscut.png]]

Another potentially useful term when it comes to tempo is the idea of a shape that we can call a '''cross cut'''. Highlighted in the previous image, are two groups of each color that both have paths though a single intersection. This happens often enough in Meridians that it might be useful to give it a name. It was also seen previously in the section on living groups, with the group living in seki creating a cross cut.

The player that can gain an extra path for one of the groups involved in the cross cut will be at an advantage, as they will be able to connect through the cross cut first cutting the opponents groups. In some cases this connecting move gains a tempo putting the opponent on the back foot, taking initiative.

You can see in the same example above that White's large group is involved in two cross cuts, and even if they could be cut across one, they would still be safe because of the other existing. Black needs to find a way to gain paths for all groups in these cross cuts to have any reasonable chance attack White's main group, and so creating one of more of these cross cuts can be a tactic to take and hold initiative, or to outright live as in the case of the seki previously.

=== The Pie rule ===

One other thing, if you're playing in Arena or just generally, is that there is a pie rule in place for balance. Before the pie rule, the White player could just play in the center, and combining that with moving first gave them an advantage it was found. With the pie rule you place one stone of each color and give the opponent the option of choosing which colour to play as.

What this means is that a) you should place stones where you think you would be happy to play as either colour, remembering White gets the first move and b) you should possibly try to balance out the first move advantage white has, by giving them a "worse" opening position, whatever that means. A guess at this might be giving white worse access to the center, either out of line with central areas, or giving Black the chance to counter attack. So possibly a white stone nearing the edge vs a black stone nearing but not exactly in the center could be balanced but it will probably depend on the specifics exactly.

It could be useful to review some Arena games, or tournament games that use the pie rule to see what some other players are trying out, but of course experiment yourself too!

File:Meridians crosscut.png

2023-09-12T12:22:20Z

Shinuito: Crosscut in meridians

== Summary ==
Crosscut in meridians

File:Meridians double path.png

2023-09-12T12:17:02Z

Shinuito: A move creating a double path in meridians

== Summary ==
A move creating a double path in meridians

File:Meridians alive.png

2023-09-12T11:04:48Z

Shinuito: An example of a living White group in meridians

== Summary ==
An example of a living White group in meridians

File:Meridians territory.png

2023-09-12T10:52:51Z

Shinuito: Territory in meridians

== Summary ==
Territory in meridians

File:Meridians capture 2.png

2023-09-12T10:29:39Z

Shinuito: Meridians capturing one of two groups

== Summary ==
Meridians capturing one of two groups

File:Meridians capture center.png

2023-09-12T10:28:21Z

Shinuito: Meridians capturing a stone in the center

== Summary ==
Meridians capturing a stone in the center

File:Meridians capture 1.png

2023-09-12T10:02:26Z

Shinuito: Example where pieces can't be saved in meridians.

== Summary ==
Example where pieces can't be saved in meridians.

Tips oust

2023-06-24T23:25:58Z

Shinuito: /* Efficiency */

== Overview ==
Oust can be a tricky game to get used to at first. The goal is to capture all your opponent's pieces, but initially there's no clear way to do this, since you can't capture or grow your own groups without your opponent's help in a sense.

Here's a brief overview of some strategic ideas and then if you wish you can read further in a dedicated section below:

* Try to place your stones in a way that gives you more '''free''' moves than your opponent. A '''free''' move is a move that either can't be captured by your opponent, or if captured gives them little to no gain in the game.
* Restrict the opponent's available moves. You don't always have to capture every stone and group of your opponent right away. If your group is strictly larger than a nearby group it could capture 2 beside 1, 3 beside 2 or 1 and so on, then you may be able to safely leave the opponent's dead stones on the board until later.
* You can sacrifice some stones in the beginning of the game to make the opponent's stones inefficient, that is they don't use the space around them effectively.
* Having too many more groups than your opponent can lose you the game.
* Allowing your opponent to have too large a group can lose you the game. It can be difficult, if not impossible to capture a group of about 20 stones on size 7 for instance.
* Having only small groups next to opponents larger groups can put you at a large disadvantage.
* Look out for the '''N+2''' rule in order to take advantage of tactics, i.e. if you have a group two sizes larger than the opponents nearby groups, there may be some tactics to take advantage of. See below for examples of tactics (trapping, lead in captures, attachments).
* Some shapes are more efficient to merge groups later, but can be vulnerable to chain capturing. Be aware of this tradeoff!

Further sections detailing the above to be created and updated soon.

==Tactics==
This section will try to give examples of short term tactics in Oust, such as chain captures, lead-in captures, trapping and attachments.

One term that might be useful to define and use could be the '''effective''' size of a group. This would be the potential size a group can become through captures that are available or will become available after an attachment. Keeping track of '''effective''' sizes of groups could be useful in determining which moves to play.

=== Attachments ===
Typically when you play directly beside an opponents stone or group, attaching/touching to that stone or group, you immediately make it stronger. Usually the opponent can choose a direction to grow their group after the attachment. This will likely become unavoidable at some stages of the game. However there are some cases where attaching has its advantages:

====Trapping====
The tactic of ''trapping'', is a particular type of attachment move, taking advantage of the rule for capturing placements, whereby you need to be larger than the opponents group you touch in order to capture it. We can think of this as an example of a free move mentioned above. Typically with these trapping moves you attach a single stone to your opponents single stone or group, in a situation where the opponent can only grow in directions where they would touch a group of the same size or larger. In these cases the opponent can't capture and it's like the group is trapped with no legal growing/capturing placements. The following images show some examples of trapping moves:

1) The easiest place to trap an opponents group is typically in corners, since there is already a limited number of directions to grow with capturing placements. Here a two stone group and an attachment traps the single brown stone.

[[File:Trapping_corner.png]]

2) An example of a three stone group and an attachment trapping two blue stones in the corner.

[[File:Trapping_two_stones.png]]

3) Trapping a single brown stone on the side of the board. It could only potentially grow in directions that touched two and three stone groups meaning it was trapped by the attachment.

[[File:Trapping_side.png]]

4) Here the single brown stone could only grow into size two and three groups after the attachment, and so was trapped by the attachment, this time in the centre of the board.

[[File:Trapping_center.png]]

==== Follow-up capture ====

Another way to use an attachment, is to create a kind of follow-up capture threat. This could either be to directly join the attachment stone back to a larger group which causes a capture, and in some cases this can potentially bring out of range groups in range of captures. Some examples of this type of follow-up capture are given below.

[[File:Oust_followupcapture.jpg]]

In the example above, blue has attached to the two brown stones, and is threatening to join back to their nearby single stone, creating a group of size 3, which will capture the two brown stones. This case is also similar to the lead-in capture (see section below) where brown has no safe direction to capture this stone without running too close to a larger group.

[[File:Oust_followupcapture2.png]]

In the second example above, which comes from the trapping example 3, with this attachment, blue is also threatening follow-up captures. Without this attachment blue could only play at the X to capture the single stone. However after this attachment, blue can instead play the sequence 1,2,3,4 to capture all the brown groups adjacent, which is an example of chain-capturing (see next section).

=== Chain Captures ===

When making a capturing placement in Oust you must take another move. This can sometimes be a good thing and other times a bad thing, depending on whether you want to be the player making a move. However it does lead to the technique of chain captures, that is, multiple captures in a row in a single turn, which can be useful throughout the game and especially with good choice of timing. A simple example of chain capturing is show below.

[[File:Oust_chain_capture.png]]

Brown has attached to a Blue piece, and this has opened up two paths for Blue to chain capture the Brown groups. Blue can choose to go Northeast and then East twice to capture three groups including the side two group, or they can choose to go Northeast three times and capture the three singleton groups shown.

One might say then that in this example that the 3 stone group has an '''effective size''' of 6, since it can become a group of size 6 when necessary. This could be useful to note when choosing which moves and sacrifices to make.

=== Lead in Captures ===
This is another way to play free moves, and a way to either delay playing detrimental moves yourself, or potentially a way to capture stones and possibly end games. The move below is an example of a lead-in capture. Blue plays a single stone in capturing range of the brown stone. However if Brown captures at the X spot, then they move in capturing range of the larger size 3 blue group, and so they have been led into a capture by a capture. If Brown doesn't capture they can be captured next by Blue. This can be a useful way to force the opponent to decide to give up on stones or be forced to capture stones.

[[File:Oust leadin.png]]

In the above case Brown could capture eastward and avoid a recapture, however in special cases that might not be an option like in the example below, Brown has no good options after the lead in capture move shown.

[[File:Oust_lead_in2.png]]

== N+2 Rule ==
Now that some examples of tactics have been looked at, for capturing groups or generating free moves, and forcing the opponent to make another move, we can consider when is it likely for tactics to arise in a game?

User manaT coined the term "N+2 rule" for Oust as a kind of heuristic on when to expect and look for tactics in Oust. Except in some special cases like the trapping tactics shown above, typically one wants to have a friendly group that is two sizes larger than neighbouring enemy groups, in order for some of the tactical ideas above to work. That is one might want a friendly size 3 or larger group near size 1 (singleton) enemy groups, size 4 beside enemy size 2 groups or smaller and so on.

In the previous sections, one could see lead in captures and follow-up captures working when surrounding groups were at least two sizes larger, or much larger than the enemy group. Here are some more examples of buying time with placements and attachments, forcing the opponent to play another move, using the N+2 heuristic:

[[File:Nplus2_1.png]]

In the above, blue has a size 4 group and so can play the lead in capture move against the size 1 group. Below, Blue has two nearby size 3 groups, and so can play the attachment to the size 1 group, threatening a follow-up capture.

[[File:Nplus2_2.png]]

== Too many groups can lose ==

This isn't a heuristic that always applies, as can be seen in some of the previous sections and equally you by definition have to have more groups than the opponent when you win. However what it should do is caution you to time your captures, and control when you make them, and how many more groups you create than the opponent.

For example, below, here's a position where the game should be completely lost for blue with good play from brown. Blue got into this position by capturing at almost every opportunity and didn't create many chances for tactics, or to force their opponent to play enough bad moves.

[[File:Oust_too_many_groups.png]]

The reason this position is losing for blue may not be completely obvious, but essentially, blue has run out of free moves, and their groups are very scattered and overall not very large (largest is size 6). Blue has no choice but to play either an attachment or at E11, which will allow brown either to start chain captures or to slowly grow and join their singletons into a larger and larger group, eventually recapturing all of blue's groups. Brown is now in control of the flow of the rest of the game.

== Game Phases and Efficiency ==
It's not strictly defined that the game has certain phases, but while playing it seems that some distinct enough gameplay emerges to merit calling these different phases of the game.

=== Opening ===
It seems reasonable to say the game is in the opening phase when there is still open space to play in where players can place new pieces that can't be immediately captured or put under threat. Players are not forced to sacrifice pieces in this phase, though they might choose to, depending on the strategy followed.

[[File:Oust_opening.png]]

Above is the example of a game of Oust in the opening phase; there is plenty of room to place a new piece without it being under threat of capture. This phase can be played in a few different ways. One can try the strategy mentioned previously, to force the opponent to make too many groups in the hopes they capture inefficiently and eventually run out of good moves. Alternatively one can try to create efficient formations of pieces, while trying to render the opponents pieces inefficiently placed. See a later section for a discussion of some ideas of efficiency.

=== Middlegame ===

There comes a point in many games of Oust where one or both players will not be able to play any new pieces that can't immediately be captured, and so players might be forced to sacrifice one or more groups they created in the opening phase.

[[File:Oust_midgame.png]]

An example of what might be called the middlegame of Oust is shown above. No new pieces can be played on the board that can't be captured, or captures are needed in order to free up space for new moves. This phase involves a lot of the tactics mentioned earlier to try to force the opponent to make more bad moves than you have to.

=== Endgame ===

Typically this might be described as a phase where players are finishing up the game, where one player has an advantage and is slowly (or rapidly) capturing their opponents groups, or it could be a close race where both players are trying to build the largest group before one is forced to be sacrificed. Some examples of this phase are shown below:

[[File:Oust_endgame.png]]

Above, blue has many groups, while brown has just one, and depending on the balance of moves and the relative sizes of groups one player will come out on top.

[[File:Oust_endgame2.png]]

Above, both players are in a close battle to make the larger group, before one inevitably has to be sacrificed when that player runs out safe moves.

=== Efficiency ===

It's not exactly easy to describe what efficiency should mean in Oust, and it is likely to change as the game is played and studied more and more, particularly efficiency in the openings. However here are a few ideas that might help you to select relatively good moves in different phases of the game.

Efficiency in the opening is tricky to define and might be subject to change, potentially even dependent on board sizes, 6,7, 8 on BGA at present. However it should somehow take into account the idea that making many separate, in particular, small groups can ultimately lead to a loss. So it stands to reason, that should you have many stones on the board, if they are densely packed, they are reasonably efficient when it comes to quickly making larger groups. That is compare the example in the section called "Too many groups can lose" to the following example:

[[File:Oust_efficient.png]]

Here while blue has many groups, the groups are much more densely packed. The marked three stones form what is called the Wheel Shape or Wheel Template in the game of Hex, and in Oust, it's possible that these three stones can be connected in one move. Playing in the centre of the wheel would be one way to stop this, but even still, these kinds of shapes mean that two stones can become a group of size 3 quickly, or three stones a size four group in a single move.

However it's worth knowing that this dense packing can be a double edged sword particularly in the opening. In the example below, blue has densely packed pieces together but either a mistake or a loss of control on the game can lead to these pieces getting chain captured all at once, which is worth keeping in mind.

[[File:Oust_efficiency_2.png]]

It's possible then that in the opening some intermediate between densely packed groups, and spaced groups provides a balance between flexibility to sacrifice and efficiency to combine.

=== Blocking efficient shapes ===

It's possible that you may want to play somewhere which forces the opponent to capture, before they can make some efficient shapes or surround some space. For instance one might see players play a move like brown does below, which 1) threatens to chain capture both blue groups and 2) prevents one wheel shape for blue.

[[File:Oust_efficiency_3.png]]

Whether this kind of move is a gain or loss is hard to tell. It's certainly a type of move that gets played a lot, and it doesn't necessarily change the effective size of the group. That is, with a wheel consisting of two singletons and a size two group, they can become a size 5 group after a single attachment. On the other hand, if one has two neighbouring size two groups, again they can become a size 5 group after one attachment.

One other way of considering this, is that brown is taking away a movement space for blue (in the wheel spot) at the cost of increasing the size of a singleton. So the real differences will show up in the tactics that play out later in the game, whether a singleton could grow to a size 2 group, or a size 2 to a size 3 group at some moment could be an important point as to who controls the flow and who is forced to sacrifice going into the middle game.

Equally it could be possible that one of the singletons in the wheel could be sacrificed without losing the adjacent groups to a chain capture, while the two size groups might both be lost together in a single chain capture.

=== Slow capturing ===

In the middle and endgame it will turn out in many instances to slowly capture singletons and groups in order to maximise the number of moves the opponent has to play where they sacrifice groups and stones. Each sacrifice should be an opportunity to grow or join your own groups, and employing some of the tactics mentioned should help you to delay captures or create larger groups when capturing quickly.

Equally it might be considered good technique in endgame to capture groups around the edges before capturing into the centre, as you may have more space for tactics and attachments there, while growing your group(s) and capturing the opponent's groups.

=== Reserving Space ===

One more idea, which is something that needs more exploration, is the idea of reserving space for yourself on the board. What this might mean is surrounding an empty point or points whereby it would be much worse for your opponent to play there while it is a move you can freely play. In this case you would reserve playing here until you really need to, and other preferred moves have all been played.

This is a bit difficult to define, because your opponent will likely always be able to play in this reserved spot, but in the examples below, you will hopefully see that it will cost the player a lot to play in order to play in these "reserved" spaces.

[[File:Oust_reserved_space_small.png]]

In this game, it might be reasonable to say that brown has reserved the spaces at A, B, C and D , because blue will not want to play here unless they plan to lose or sacrifice many of their stones. Some of the lines drawn show the possible chain captures should blue play any of A through D. In contrast a point like E, is one neither player really wants to play, should brown play E the stone on D4 can be chain captured or blue can consider the 1,2 combo. If blue plays E, the two blue groups in the corner are dead.

There's a few more points one might consider reserved for brown should you want to continue to examine this position.

File:Oust reserved space small.png

2023-06-24T23:18:36Z

Shinuito: Idea of reserving spaces in Oust

== Summary ==
Idea of reserving spaces in Oust

File:Oust efficiency 3.png

2023-06-24T22:56:06Z

Shinuito: A move to block an efficient move for Blue?

== Summary ==
A move to block an efficient move for Blue?

File:Oust efficiency 2.png

2023-06-24T22:42:27Z

Shinuito: Oust efficiency double edged sword

== Summary ==
Oust efficiency double edged sword

File:Oust efficient.png

2023-06-24T22:35:49Z

Shinuito: Attempt at describing efficient shapes in Oust

== Summary ==
Attempt at describing efficient shapes in Oust

Tips oust

2023-06-24T21:55:05Z

Shinuito: Adding a section defining phases of the game - will discuss efficiency in those phases soon

File:Oust endgame2.png

2023-06-24T21:44:53Z

Shinuito: Oust endgame example 2

== Summary ==
Oust endgame example 2

File:Oust endgame.png

2023-06-24T21:43:31Z

Shinuito: Oust endgame example 1

== Summary ==
Oust endgame example 1

File:Oust midgame.png

2023-06-24T21:36:11Z

Shinuito: Middlegame of Oust

== Summary ==
Middlegame of Oust

File:Oust opening.png

2023-06-24T21:31:29Z

Shinuito: Opening of a game of oust

== Summary ==
Opening of a game of oust

Tips oust

2023-06-24T17:44:01Z

Shinuito: Adding a section on having too many groups

File:Oust too many groups.png

2023-06-24T17:37:42Z

Shinuito: /* Summary */

== Summary ==
Blue runs out of good moves

File:Oust too many groups.png

2023-06-24T17:37:30Z

Shinuito: Blue runs out of moves

== Summary ==
Blue runs out of moves

File:Nplus2 2.png

2023-06-24T17:27:31Z

Shinuito: Example of tactics using the N+2 rule.

== Summary ==
Example of tactics using the N+2 rule.

File:Nplus2 1.png

2023-06-24T17:26:55Z

Shinuito: Example of tactics with the N+2 rule

== Summary ==
Example of tactics with the N+2 rule

File:Oust followupcapture2.png

2023-06-24T17:07:24Z

Shinuito: Shinuito uploaded a new version of File:Oust followupcapture2.png

== Summary ==
Oust follow up capture example 2

Tips oust

2023-06-24T16:59:53Z

Shinuito: Expand the tactics section with many more examples.

File:Oust followupcapture2.png

2023-06-24T16:57:25Z

Shinuito: Oust follow up capture example 2

== Summary ==
Oust follow up capture example 2

File:Oust followupcapture.jpg

2023-06-24T16:54:39Z

Shinuito: Oust follow up capture example

== Summary ==
Oust follow up capture example

File:Oust lead in2.png

2023-06-24T16:37:30Z

Shinuito: An example of winning with a lead in capture.

== Summary ==
An example of winning with a lead in capture.

File:Oust chain capture.png

2023-06-24T16:21:21Z

Shinuito: Chain captures in Oust

== Summary ==
Chain captures in Oust

File:Oust leadin.png

2023-06-24T16:15:20Z

Shinuito: Example of lead in capture in Oust.

== Summary ==
Example of lead in capture in Oust.

Tips oust

2023-06-24T15:45:11Z

Shinuito: grammar and small additions

Gamehelpmartianchess

2023-06-24T11:06:56Z

Shinuito: /* Gameplay */

==Gameplay==
* Each player gets a 4*4 board and fits them together. This is each player's territory.
* Each player gets 3 pawns (one dot), 3 drones (two dots) and 3 queens (three dots) and places them in their territory. Colours don't matter.
* On your turn, move a piece in your territory. If you move onto an opponent's piece, you capture it.
* Pawns can move one space diagonally, drones can move up to two spaces orthogonally (at right angles) and queens can move any number of spaces in any direction.
* You can merge a drone and a pawn to a queen if you have no queens, and merge two pawns to a drone if you have no drones.
* In a 2-player game, your opponent may not “reject” your move; if one player moves a piece across the canal, the other can’t move it back to the same square it came from.

==End of the Game==
* The game ends when a territory is empty.
* Each player scores 1 point for a dot on a piece they capture. The player with the most points wins.
* If there is a tie, the player who makes the move causing the game to end is the winner, regardless of points.

Tips rive

2023-03-23T11:33:03Z

Shinuito: Added a section on effective sizes of groups

It's worth playing a few games of Rive first, reading and absorbing the rules.

In short the key points of the rules are:

(0). groups are connected adjacent stones where the colour is unimportant.

(1). Singletons '''must''' be played when possible.

(2). Stones can only be placed which are adjacent to up to three groups where the largest group is as small as possible.

(3). When you join groups (capturing placement) you need to remove stones from the newly merged group to make it one larger than the largest group being merged. You '''must''' play again after this type of placement.

It can take some time to absorb how this works in practice and what it means for the gameplay, but below it will detail some consequences of the rules, how the game breaks up into phases from these rules, and how one can try to tactically keep control of the initiative or momentum in the game.

=== Phase 1: Singletons ===

Players must place singletons at the start of the game until no more singletons are possible to place as per point (1) above. In this phase you want to force your opponent to play the last singleton so you will have the chance to merge singletons and keep control of the game. This is an example of the end of the singleton phase, any new stone will touch at least one singleton.

[[File:Rive_singletons.png]]

==== Winning the singleton phase ====

In order to "win" the singleton phase, that is have the first move at the end of this phase, you need to force the opponent to play the last singleton. One way to achieve this is to create a situation where your opponent is to move but there's an odd number of single placements left, 1,3,5 etc as in the example below. It's red to move, and there's an odd number of placements left so blue is winning.

[[File:Singleton1.png]]

This was the simplest case, but knowing this you can start to learn additional shapes and predict which player has the advantage. For example if there are two straight or slightly bent 3 shapes as in the image below, the player to move is "losing" in the opening.

[[File:Singleton2.png]]

In this case blue has to make a move, if they play in the centre of the three spaces, red can play on the corner of the opposite 3 space and leave the last move for blue. Similarly if blue plays on an edge, red can play in the centre on the opposite three spaces. So this is a 'winning' position for the second player.

You can work out similar examples in your own games, an easy follow on would be to work out who is winning if there's two of these straight threes and a singleton space as well.

=== Phase 2: Group building and merging ===

After all the singletons are placed one player will then have the option to either play adjacent to a singleton or join two singletons and then remove one of the two stones as per point (3) above, two is one larger than the merged singletons.

One simple strategy in this phase will be to try to build all of the groups up a level at a time and retain control of the initiative. You might grow the singletons all to size 2, then afterward grow the groups to size 3, 4, 5 etc. Typically you'd like to remove as many of your opponents stones as you can, but that not might always be advisable. Sometimes you'll have to remove your own stones for a better position first.

For instance in the above game at the end of all the singletons the player in control might try to merge many of the singletons into size 2 groups as below.

[[File:Groups1.png]]

It can be the case that you can no longer merge any groups, for instance because they are far apart, or possibly you don't want to merge them because it will give the opponent the initiative to decide the next sequence of moves.

There's a useful tactic in the situation above.

==== Parallel Growing of groups ====

You can use point (2) above to control where the opponent can play in certain situations in the game, either by forcing them to place a singleton, which we'll see in the next section, or you can force them to grow a particular group. In this case red played F1 and blue is now forced to grow the other singleton group to size 2, since this would be the group that is as small as possible - they're not allowed to play a move adjacent to both a singleton and size 2 group for instance.

[[File:Parallelgrowing1.png]]

Another example where the player to move (it was red in this case), can parallel grow the two size 3 groups into size 4 groups which is forced by point (2).

[[File:Parallelgrow2.png]]

This can be useful at many places in this phase in the game, but one point in particular where it is pretty useful is in ending the game and transitioning to the last phase of the game.

[[File:Parallelgrow3.png]]

In the example above, it has reached a point with only two large equally sized groups. It was red to play, and red can now parallel grow both groups, red grows one, and blue is forced to grow the other by point (2) again.

The reason why you might want to parallel grow these groups is that when merged you'll need to remove more stones, the larger the groups being merged.

A merging rule of thumb would be:

'''If merging two size N groups you will need to remove N stones.'''

So in the above case merging two size 5 groups requires removing 6 stones and freeing up a lot of empty space.

Here's two more tactics that one can use when merging groups.

==== Forced singletons and growing ====

In order to retain initiative, momentum, control of the flow of the game, you want to make sure that when you open new space, your opponent is forced to place the last move and doesn't have the option to merge groups.

Similar to phase 1, one way to do this is to force them to place a singleton. In the example below blue merged singletons to create a size 2 group and open up a space of size 3. If they play at A, then red will be forced to play at B or vice versa, which gives blue back control to make the next merging move etc.

[[File:Forcedsingleton.png]]

Similar to this one can also force the opponent to grow the only group of a certain size, be that a singleton or large size group using point (2) above. So in the following position below red merged groups to make a size 3 group, leaving two adjacent empty spaces and had to play a singleton, the piece marked X. However since this is the only singleton, and there is a space available which doesn't touch other groups, blue is forced to grow the singleton with the move at A.

[[File:Forcedgrow.png]]

==== Effective sizes ====

One other useful idea for retaining control of the game is to create a situation where a smaller group is boxed in by larger groups as below.

[[File:Rive_effective_size.png]]

In the above image Red is growing groups to size three, and if there was any adjacent space to the size two group touching no other groups, this growing move would be forced. However since all moves adjacent to the size two groups (the spots marked with X's) are also adjacent to size three groups, you can effectively treat this size two group as though it were size three for the purposes of growing groups.

In this situation all moves become legal again, because every move touches a size 3 group, similar to when there are only size three groups on the board.

Red can now remove the size two group by merging with the one of size three groups and continue on to growing size 4 groups.

==== 2nd line stones and removing from the edges ====

It can be useful to control and keep stones on the second line of the board, that is the second from outermost ring on the board. The reason for this is that since it is adjacent to the edge, new stones placed there will have touch the second line stone(s) and that might mean forbidding these edge moves from being legal. This can be useful to keep initiative in the game, controlling legal moves.

For example in the position below blue has just joined two large groups of size 11 so 11 stones will need to be removed.

[[File:Removeedges.png]]

In this example it will be good for blue to remove as many red stones as possible, and in particular to remove stones from the edges in order to move the game into the third and final phase. So for example removing edge stones and keeping second line stones will set blue up for a win. This example will be continued in phase 3 along with another example.

=== Phase 3: Filling in ===

As mentioned previously there is a third phase of the game. This is where there is just one large group with no room for singletons or other smaller groups on the board. All future moves will have to grow this group, and this group is as small as possible being the only group.

[[File:Phase3.png]]

Blue preferentially removed red pieces and pieces around the edges, and so now both players would take turns placing one stone at a time to grow this group by 1. However red can't catch up on blue at this point, since both players will increase their score by 1 until the game ends. So the result is already decided.

Here's another situation where both players have 5 stones each, and the game has reached phase 3. The next player to move wins, since the score difference won't change with each pair of moves, but there's an odd number of points on the board, and so and odd number of moves left.

[[File:Phase3_eg2.png]]

Taking turns filling in blue wins by 1 point.

[[File:RiveEnding.png]]

File:Rive effective size.png

2023-03-23T11:26:28Z

Shinuito: Rive game where a size 2 group can effectively treated as size 3.

== Summary ==
Rive game where a size 2 group can effectively treated as size 3.

Tips rive

2023-03-13T23:51:08Z

Shinuito: An attempt at a strategy guide to rive. Apologies for replacing the previous wiki.

It's worth playing a few games of Rive first, reading and absorbing the rules.

In short the key points of the rules are:

(0). groups are connected adjacent stones where the colour is unimportant.

(1). Singletons '''must''' be played when possible.

(2). Stones can only be placed which are adjacent to up to three groups where the largest group is as small as possible.

(3). When you join groups (capturing placement) you need to remove stones from the newly merged group to make it one larger than the largest group being merged. You '''must''' play again after this type of placement.

It can take some time to absorb how this works in practice and what it means for the gameplay, but below it will detail some consequences of the rules, how the game breaks up into phases from these rules, and how one can try to tactically keep control of the initiative or momentum in the game.

=== Phase 1: Singletons ===

Players must place singletons at the start of the game until no more singletons are possible to place as per point (1) above. In this phase you want to force your opponent to play the last singleton so you will have the chance to merge singletons and keep control of the game. This is an example of the end of the singleton phase, any new stone will touch at least one singleton.

[[File:Rive_singletons.png]]

==== Winning the singleton phase ====

In order to "win" the singleton phase, that is have the first move at the end of this phase, you need to force the opponent to play the last singleton. One way to achieve this is to create a situation where your opponent is to move but there's an odd number of single placements left, 1,3,5 etc as in the example below. It's red to move, and there's an odd number of placements left so blue is winning.

[[File:Singleton1.png]]

This was the simplest case, but knowing this you can start to learn additional shapes and predict which player has the advantage. For example if there are two straight or slightly bent 3 shapes as in the image below, the player to move is "losing" in the opening.

[[File:Singleton2.png]]

In this case blue has to make a move, if they play in the centre of the three spaces, red can play on the corner of the opposite 3 space and leave the last move for blue. Similarly if blue plays on an edge, red can play in the centre on the opposite three spaces. So this is a 'winning' position for the second player.

You can work out similar examples in your own games, an easy follow on would be to work out who is winning if there's two of these straight threes and a singleton space as well.

=== Phase 2: Group building and merging ===

After all the singletons are placed one player will then have the option to either play adjacent to a singleton or join two singletons and then remove one of the two stones as per point (3) above, two is one larger than the merged singletons.

One simple strategy in this phase will be to try to build all of the groups up a level at a time and retain control of the initiative. You might grow the singletons all to size 2, then afterward grow the groups to size 3, 4, 5 etc. Typically you'd like to remove as many of your opponents stones as you can, but that not might always be advisable. Sometimes you'll have to remove your own stones for a better position first.

For instance in the above game at the end of all the singletons the player in control might try to merge many of the singletons into size 2 groups as below.

[[File:Groups1.png]]

It can be the case that you can no longer merge any groups, for instance because they are far apart, or possibly you don't want to merge them because it will give the opponent the initiative to decide the next sequence of moves.

There's a useful tactic in the situation above.

==== Parallel Growing of groups ====

You can use point (2) above to control where the opponent can play in certain situations in the game, either by forcing them to place a singleton, which we'll see in the next section, or you can force them to grow a particular group. In this case red played F1 and blue is now forced to grow the other singleton group to size 2, since this would be the group that is as small as possible - they're not allowed to play a move adjacent to both a singleton and size 2 group for instance.

[[File:Parallelgrowing1.png]]

Another example where the player to move (it was red in this case), can parallel grow the two size 3 groups into size 4 groups which is forced by point (2).

[[File:Parallelgrow2.png]]

This can be useful at many places in this phase in the game, but one point in particular where it is pretty useful is in ending the game and transitioning to the last phase of the game.

[[File:Parallelgrow3.png]]

In the example above, it has reached a point with only two large equally sized groups. It was red to play, and red can now parallel grow both groups, red grows one, and blue is forced to grow the other by point (2) again.

The reason why you might want to parallel grow these groups is that when merged you'll need to remove more stones, the larger the groups being merged.

A merging rule of thumb would be:

'''If merging two size N groups you will need to remove N stones.'''

So in the above case merging two size 5 groups requires removing 6 stones and freeing up a lot of empty space.

Here's two more tactics that one can use when merging groups.

==== Forced singletons and growing ====

In order to retain initiative, momentum, control of the flow of the game, you want to make sure that when you open new space, your opponent is forced to place the last move and doesn't have the option to merge groups.

Similar to phase 1, one way to do this is to force them to place a singleton. In the example below blue merged singletons to create a size 2 group and open up a space of size 3. If they play at A, then red will be forced to play at B or vice versa, which gives blue back control to make the next merging move etc.

[[File:Forcedsingleton.png]]

Similar to this one can also force the opponent to grow the only group of a certain size, be that a singleton or large size group using point (2) above. So in the following position below red merged groups to make a size 3 group, leaving two adjacent empty spaces and had to play a singleton, the piece marked X. However since this is the only singleton, and there is a space available which doesn't touch other groups, blue is forced to grow the singleton with the move at A.

[[File:Forcedgrow.png]]

==== 2nd line stones and removing from the edges ====

It can be useful to control and keep stones on the second line of the board, that is the second from outermost ring on the board. The reason for this is that since it is adjacent to the edge, new stones placed there will have touch the second line stone(s) and that might mean forbidding these edge moves from being legal. This can be useful to keep initiative in the game, controlling legal moves.

For example in the position below blue has just joined two large groups of size 11 so 11 stones will need to be removed.

[[File:Removeedges.png]]

In this example it will be good for blue to remove as many red stones as possible, and in particular to remove stones from the edges in order to move the game into the third and final phase. So for example removing edge stones and keeping second line stones will set blue up for a win. This example will be continued in phase 3 along with another example.

=== Phase 3: Filling in ===

As mentioned previously there is a third phase of the game. This is where there is just one large group with no room for singletons or other smaller groups on the board. All future moves will have to grow this group, and this group is as small as possible being the only group.

[[File:Phase3.png]]

Blue preferentially removed red pieces and pieces around the edges, and so now both players would take turns placing one stone at a time to grow this group by 1. However red can't catch up on blue at this point, since both players will increase their score by 1 until the game ends. So the result is already decided.

Here's another situation where both players have 5 stones each, and the game has reached phase 3. The next player to move wins, since the score difference won't change with each pair of moves, but there's an odd number of points on the board, and so and odd number of moves left.

[[File:Phase3_eg2.png]]

Taking turns filling in blue wins by 1 point.

[[File:RiveEnding.png]]

File:Forcedgrow.png

2023-03-13T23:45:51Z

Shinuito: forced growing in Rive

== Summary ==
forced growing in Rive

File:Forcedsingleton.png

2023-03-13T23:40:46Z

Shinuito: Forcing the opponent to play a singleton in Rive

== Summary ==
Forcing the opponent to play a singleton in Rive

File:RiveEnding.png

2023-03-13T23:34:35Z

Shinuito: End of a rive game.

== Summary ==
End of a rive game.

File:Phase3 eg2.png

2023-03-13T23:32:23Z

Shinuito: Another rive game in phase 3 near the end

== Summary ==
Another rive game in phase 3 near the end