Japanese flower cards — match the months and decide whether to press on.
Played with hanafuda — Japanese flower cards — rather than a 52-card deck. Two players match cards by month and then decide whether to stop or press on.
48 hanafuda cards, twelve months of four cards each. Within a month the cards differ in value: brights, animals, ribbons and plain cards.
Eight cards to each player, eight face up on the table, and the rest face down as the draw pile.
Play a card from your hand that matches the month of a card on the table, and take both. If nothing matches, lay your card on the table.
Then turn the top card of the draw pile and do the same with it — match and capture, or leave it on the table.
So you may capture twice in a turn, or not at all.
Captured cards are sorted into scoring combinations. The main ones:
Five brights: 10 points. Four brights: 8. Three brights: 5. Boar, deer and butterfly: 5 points. Flower or moon viewing with sake cup: 5 points each. Ribbons of one colour, three of them: 5 points. Five or more animals: 1 point, plus 1 per extra. Five or more ribbons: 1 point, plus 1 per extra. Ten or more plain cards: 1 point, plus 1 per extra.
When you complete a yaku you choose: stop, and score what you have — or call koi-koi and keep playing for more.
Call koi-koi and your opponent completing any yaku afterwards ends the round and scores for them instead, doubled. That single decision is the entire game.