Koi-Koi
Koi-Koi (こいこい) is a popular card game in Japan and Korea played with Flower Cards.
The object of the game is to form special card combinations called 'yaku' from cards accumulated in your point pile. You can gain cards in your point pile by matching cards in your hand, or drawn from the draw pile, with cards on the table. Once you have made a yaku, you can stop to cash in your points, or keep going (referred to as 'koi-koi,' hence the name of the game) to form additional yaku for more points. The point values assigned to individual cards have no effect on the score, but they are helpful to judge their value in forming yaku.
Deal
An initial dealer (called the 'oya', or 'parent'), is decided upon when the game starts. This can be done with any method (rock-paper-scissors, dice roll) the players agree upon. A hanafuda-specific method involves random card draw: each player draws a single card; the player who draws a card from the earliest month is the oya.
To deal, the oya deals eight cards to his opponent (face down), the table (face up), then to himself (face down), though this is normally done two or four cards at a time. The rest of the cards are set aside as a draw pile, and then play begins starting with the oya.
Play
On a player's turn, he may match by suit (i.e. month or flower) any one card in his hand with one on the table, and take both into his point pile. Alternatively, he may discard any one card from his hand face up to the table (which is his only choice if he can not match anything). After matching or discarding a card, he then draws one card from the draw pile and places it face up on the playing area. If this card matches any card now on the table, he must match that card and keep both for his point pile; otherwise, he must discard it face up to the table. In the event that the drawn card matches more than one card on the table, the player gets the choice as to which card to match and therefore keep in addition to the drawn card.
After a player's turn ends, if he made at least one yaku that turn, that player must then make a choice. He may stop play and gain all the points he is entitled to from the yaku he has, or he can choose for play to continue (calling 'koi-koi') in an effort to gain more points. Once a player calls the game the hand is over, points are tallied, and a new hands begins.
The purpose of calling koi-koi is to be able to gain more points before ending a hand. It is possible to call koi-koi as many times as one likes, each time a yaku is formed. However, if the player's opponent is able to form a yaku before the player who called koi-koi, the opponent's score is doubled and the player's score is reduced to zero. If a player gains yaku totaling 7 or more points when the hand is called, his score is doubled. If a player beats his opponent to a yaku after the opponent calls koi-koi in addition to scoring 7 or more points of yaku, his initial yaku score is quadrupled.
The player with the most points at the end of the hand becomes the new oya, and a new hand is dealt. Should both players ever run out of cards to play without having formed a yaku on the last play, no points are awarded to either player, and the next hand begins with the same oya. Generally play continues for 12 hands, but the players can decide to play for a different number of rounds before the game starts.
Some groups, when gambling, will require the player whose score was multiplied to pay a proportionately larger amount of the winnings (i.e. a player who continued play twice would pay twice as much as the other player, since his score would have been doubled).
Special Cards
The Sake Cup is unique in that, though technically classified as a 10-point card, it counts as both a 10-point card and a 1-point card at the same time. Some rules allow the Sake Cup to count as a 10-point card and two 1-point cards at the same time.
Additionally, November's 1-point card, the Lightning, is sometimes used as a wild card that can match any card in some games.
Yaku Listing
If certain combinations of cards are won during play, extra points apply. Sometimes, players will be paired across the table when this rule is used (in multi-player Koi-Koi) to increase the chance of getting combos. Below is a list of special combinations with point values.
Some yaku can be considered extensions of others. For example, one may qualify for both Akatan and Tan by having the Akatan combination as well as two additional five-point cards. In these cases, players are only awarded points for the highest value yaku the associated cards qualify for.
| Points | Combo Name | Card Combo |
|---|---|---|
| 5 | Sankō (三光) | Any three 20-point cards excluding the Rainman (Willow's 20-point card). |
| 8 | Shikō (四光) | The four 20-point cards which exclude the Rainman (Willow's 20-point card). |
| 7 | Ame-Shikō (雨四光) | Any four 20-point cards including the Rainman (Willow's 20-point card). |
| 10 | Gokō (五光) | All five 20-point cards. |
| 5 | Inoshikachō (猪鹿蝶) | The Boar, the Deer, and the Butterflies (the 10-point cards from Clover, Maple, and Peony, respectively). One additional point is awarded for every additional 10-point card. |
| 1 | Tane (タネ) | Any five 10-point cards, such as animals, the Docks (Iris), or the Sake Cup (Chrysanthemum). One additional point is awarded for every additional 10-point card. |
| 5 | Akatan (赤タン) | All 3 Red Poetry Ribbons (found in Pine, Ume, and Sakura). One additional point is awarded for every additional 5-point card. |
| 5 | Aotan (青タン) | All 3 Purple/Blue Ribbons (found in Peony, Crysanthemum, and Maple). One additional point is awarded for every additional 5-point card. |
| 10 | Akatan, Aotan no Chōfuku (赤短・青短の重複) | All 3 Red Poetry Ribbons and all 3 Purple/Blue Ribbons: the combination of Aka-tan and Ao-tan. One additional point is awarded for every additional 5-point card. |
| 1 | Tan (タン) | Any five 5-point cards, which includes all Ribbons. One additional point is awarded for every additional 5-point card. |
| 5 | Tsukimi-zake (月見酒) | The Moon and the Sake Cup (Pampas' 20-point card and Crysanthemum's 10-point card). Cumulative with Hanami-zake. |
| 5 | Hanami-zake (花見酒) | The Sakura Banner and the Sake Cup (Sakura's 20-point card and Crysanthemum's 10-point card). Cumulative with Tsukimi-zake. |
| 1 | Kasu (カス) | Any ten 1-point cards, which are all normal (or literally, 'junk') cards. One additional point is awarded for every additional 1-point card. |
Instant Wins and Redeals
There are two special yaku such that, if a player is dealt them before play begins, he is immediately awarded points. Play then ends before it starts, and the game continues to the next hand. These two combinations are as follows.
| Points | Combo Name | Card Combo |
|---|---|---|
| 6 | Teshi (手四) | Being dealt four cards of the same suit. |
| 6 | Kuttsuki (くっつき) | Being dealt four pairs of cards with matching suits. |