- Each player is dealt 8 cards and 8 cards are placed in the middle.
- One player goes first.
- If a instant winning hand is dealt it is scored and a new round is started.
- Otherwise play as normal.
- On your turn, you can capture a card in the middle with a card from your hand.
- Those cards must be of the same month.
- Place the card from your hand and the captured card in your winning zone.
- Otherwise you must discard a card and place it in the middle.
- Draw a card from the deck
- You must capture if possible
- Otherwise it is discarded
- If there are 3 cards from the same month they are placed in a stack.
- The player with the last card from that month may capture the stack.
- If you form a yaku you must either score it or shout koi-koi.
- If scored, you get those points multiplied by the multiplier and the round end.
- If not scored, the round continues and you cannot score that yaku until you have formed another yaku.
- If an opponent scores a yaku, you lose your points.
- End the game after a number of rounds (or months).
- At the end of the game, the player with the most points (or kobans) wins!
About yaku (card combinations)
You can use the in game help icon to display a popup listing all the possible yaku and how many points they are worth.
All the yaku are combinative, except the "Bright" cards yaku, which are exclusive (you will always score the biggest available).
As is often the case with traditional games, there are a lot of variants for playing Koi-koi, especially in regards to scoring.
For Board Game Arena, two variants are provided through the options when creating the game:
Adapted from the Sloperama site rules which is all about saying "Koi!". Of course you run the risk of your opponent making a yaku and scoring for the month (round) before you can score yourself, but in exchange for that risk, each time you will get a multiplier so that if you manage to increase your score with another yaku, you will score a lot more. This is an aggressive variant with a lot of points available if you push your luck.
Adapted from the Hanafubuki site rules which is less incentive to call "Koi!" since you won't get a multiplier just for saying "Koi!". Instead, your opponent will! If you say "Koi!" at least once, then if your opponent manages to score their score will be doubled. Still, at some point you'll risk it, because if you manage to improve your yaku to score 7 points or more, then your score will be doubled.
Please also note how draws are handled:
- if a month ends by lack of cards in hand, the hand ends without scoring. This can be changed by lobby options (either dealer or non-dealer scores 6 points instead).
About "Viewing" yaku
A few variants have been implementend for the "Viewing the Moon" and "Viewing the Cherry Blossoms" yaku:
Viewing yaku enabled
Both yaku are available (this is the default).
Rain ruins the party
If a player captures at least one card of November (rain), the party is ruined, both yaku are unavailable for this player.
Viewing yaku disabled
Both yaku are unavailable.
About "First play"
Getting the first play (and thus being the first to choose from the field) is a nice advantage. Some variants have been made available upon request:
Winner starts the next month
The winner for the current month gets to play first the next month (this is the default).
Loser starts the next month
The player who lost this month gets to play first the next month.
Alternate starting player
The player who didn't get to play first this month will play first the following month.