Hanafuda Koi-Koi: Rules, Yaku and Strategy

Hanafuda, "flower cards", are the survivors of a long argument between Japan and playing cards. Portuguese sailors brought European cards in the sixteenth century; the shogunate banned gambling with them; players responded with new decks that looked less like the banned ones, and the designs kept evolving until the numbers and suits were gone entirely and only pictures remained. The result is a 48-card deck of twelve months, each painted with its flower or plant, and a set of games built around matching those months. In 1889 a small Kyoto workshop began printing hanafuda commercially; that company was Nintendo, and it still prints them today.

Koi-Koi is the two-player game almost everyone plays with the deck. It is fast, it is mostly luck early and mostly nerve late, and it is named after the decision that defines it.

The deck: twelve months, four cards each

Every month has four cards showing the same plant. Within each month the cards differ in value:

• Brights (hikari): five in the deck, the highest cards. January's crane with the sun, March's cherry-blossom curtain, August's full moon over pampas grass, November's rain man (a poet with an umbrella) and December's phoenix over paulownia.
• Animals (tane): nine cards showing a creature or object: the February bush warbler, April cuckoo, May bridge, June butterflies, July boar, September sake cup, October deer, November swallow, and the August geese.
• Ribbons (tanzaku): ten cards with a strip of paper. Three are red with poetry (January, February, March), three are blue (June, September, October), and four are plain red.
• Chaff (kasu): the remaining 24 plain cards, one point each.

The months in order: pine, plum, cherry, wisteria, iris, peony, bush clover, pampas grass, chrysanthemum, maple, willow, paulownia. Learning to recognise the plant of each month is the first and only memorisation Koi-Koi requires.

Setup

Shuffle and deal eight cards to each player and eight face up to the table (the field), leaving the rest as a draw pile. If the field shows four cards of the same month, or the dealer holds four of a month, the hand is redealt. The dealer (oya) plays first; the winner of a round deals the next.

How a turn works

On your turn:

1. Play a card from your hand. If it matches the month of a card on the field, take both and put them face up in your capture pile. If it matches nothing, leave it on the field. If it matches two field cards, you choose which to take; if it matches three, you take all four.
2. Flip the top card of the draw pile. Apply the same matching rule: capture a matching field card, or leave the drawn card on the field.

Captured cards stay visible so both players can see what combinations are forming. The round ends when a player calls a win, or when both hands are empty, in which case nobody scores (in most house rules the dealer scores nothing but keeps the deal).

The koi-koi decision

Whenever a capture completes a yaku (a scoring combination) in your pile, you must choose:

• Stop (shobu): the round ends and you score every yaku in your pile.
• Koi-koi: the round continues. If you later complete a new yaku, or improve an existing one, you can stop then and score everything. But if your opponent completes a yaku and stops first, you score nothing for the round, and in most rule sets your opponent's score is doubled because you called koi-koi.

That gamble is the whole game. Early yaku are usually worth stopping on; a big hand with several near-complete combinations is worth the risk. The word itself means roughly "come on, keep going".

Every yaku is a question: take the small sure thing now, or say koi-koi and let the cards decide.

The standard yaku

Points vary slightly between rule sets; these are the common values.

• Five Brights (gokou): all five brights. 10 points.
• Four Brights (shikou): four brights without the rain man. 8 points.
• Rainy Four Brights (ame-shikou): four brights including the rain man. 7 points.
• Three Brights (sankou): three brights without the rain man. 5 points.
• Boar-Deer-Butterfly (inoshikachou): the July boar, October deer and June butterflies. 5 points, plus 1 per extra animal.
• Poetry Ribbons (akatan): the three red poetry ribbons. 5 points, plus 1 per extra ribbon.
• Blue Ribbons (aotan): the three blue ribbons. 5 points, plus 1 per extra ribbon.
• Moon Viewing (tsukimi-zake): the August moon with the September sake cup. 5 points (some tables disable it).
• Cherry Blossom Viewing (hanami-zake): the March curtain with the sake cup. 5 points (same caveat).
• Ribbons (tan): any five ribbons. 1 point, plus 1 per extra.
• Animals (tane): any five animals. 1 point, plus 1 per extra.
• Chaff (kasu): any ten chaff cards. 1 point, plus 1 per extra. The sake cup may count as chaff in some rules.

A round's total of 7 points or more is often doubled. The full table with regional variants is in the Hanafuda chapter of The Mind Games of Japan.

Simple strategy

• Count the brights. There are only five. If your opponent holds two and a third is on the field, do not feed it; discard a card of a different month.
• Chaff wins more rounds than you think. Ten chaff is a slow, safe yaku that keeps the option to stop. Take chaff matches when nothing better is offered.
• Watch the discards. Every card you see leaves at most three of that month. If three cards of a month are gone, the fourth is worthless to both players.
• Stop early when behind on the deal. The dealer moves first and sees one more draw over the round; as the second player, take modest sure points.
• Koi-koi with cover. Call koi-koi when you have a second yaku one card away and your opponent shows nothing close. Never call it just because the yaku is small.

Where to go next

Play a few rounds with the yaku list beside you; the months become automatic quickly and the koi-koi decision becomes the whole conversation. For the three-player hanafuda game with richer scoring, Hachi-Hachi, and for the card game of a hundred poems that uses a completely different deck, see competitive karuta explained and the Hanafuda chapter of the MyRin ebook.

FAQ

How many cards are in a hanafuda deck?

48 cards: twelve months of four cards each. Every month is painted with one plant, from January pine to December paulownia, and the four cards of a month are matched to each other during play.

What does koi-koi mean?

Koi-koi means roughly "come on, keep going". When you complete a yaku you may stop and score, or call koi-koi to continue the round and try for a bigger combination. If your opponent then scores first, you get nothing for the round.

What is the highest yaku in Koi-Koi?

Five Brights (gokou), all five bright cards: crane, curtain, moon, rain man and phoenix. It is worth 10 points in most rule sets. Four Brights without the rain man scores 8 and Rainy Four Brights (with the rain man) scores 7.

Is Hanafuda the same as Koi-Koi?

No. Hanafuda is the deck; Koi-Koi is the most popular two-player game played with it. Other hanafuda games include Hachi-Hachi (a three-player game with more elaborate scoring) and Hana-Awase.