Rules of Hachi-hachi

Hachi-hachi is a Hanafuda game played in 6 or 12 rounds.
A month (1 round) consists of a bidding phase, a playing phase, and a scoring phase.

• One set of Hanafuda (12 suits, 4 cards each) is used.
• Hachi-hachi can be played with 3 to 6 players, but each playing phase is played with only three players. In the bidding phase, players will determine whether they will join the playing phase or sit out that round.

• The units of scoring are kan and mon. 1 kan is equivalent to 12 mon.
  ~ mon values are always written as a zero or a positive number. For example, if you're forced to pay 5 mon, it will be displayed as "-1 kan 7 mon". (-12 mon +7 mon)
  ~ Your score on BGA is your kan value. mon is used only to break ties in final scoring.

Kan can neither be created nor destroyed.

• All points (kan and mon) are paid from one player to another. There is no central bank, and any loss or gain of points will be equally split among the players affected.
• Whenever you gain kan during the playing or scoring phase, you take half that amount from each opponent who called "In the Play" that round.
  ~ For example, if you gained 5 kan from a yaku, you would take 2.5 kan each from your two opponents that round.

Special rule: All Willow (December) suit cards count as Chaff cards when determining hand yakus (Te-Yaku), card-set yakus (Deki-Yaku), and special-scoring yakus (Tokushu-Yaku).

Initial Setup

• Randomly determine the dealer (1st player) and seating order.
• Initial ante: Each player begins the game with -5 kan in a full game, or -3 kan in a half game.

Setup for each month (1 round)

• Before dealing any hands, the dealer may call "Mizuten". This commits them to "Join the Play" that round without knowing their hand's contents. If they do, they take 1 kan from each "Get Out of Play" player at the start of the playing phase.
• The dealer deals 7 cards to each player, then deals 6 cards to the table.

• Determine the scoring multiplier for the round (Small deal = 1x; Big deal = 2x; Great deal = 4x).
  ~ If no Bright cards appear on the table, the deal is a "small deal" and no multiplier is applied. (1x)
  ~ If a Bright card of Pine, Cherry-Blossom or Eulalia appears on the table, the deal is a "big deal", and all subsequent gains and losses are doubled. (2x)
  ~ If a Bright card of Willow or Paulownia appears on the table, the deal is a "great deal", and all subsequent gains and losses are quadrupled. (4x)
  ~ If more than one Bright card appears in the table, apply the higher multiplier to this round, and carry the lower multiplier over to the next round.

Bidding phase

• Starting with the dealer, each player looks at their hand and declares whether they want to "Join the Play" or "Get Out of Play".
  ~ If the dealer called "Mizuten" before looking at their hand, they must "Join the Play".
  ~ If the player chooses "Join the Play", they commit to playing their hand for that round.
  ~ If the player chooses "Get Out of Play", they sit out this round. The first player to call "Get Out of Play" pays 1 kan, the second player pays 1.5 kan, and the third player pays 2 kan.

• If three players call "Join the Play", all remaining players must call "Get Out of Play".
  ~ Players who called "Get Out of Play" will receive points according to their hand yakus (Te-Yaku) from the players who called "Join the Play".
• If three players call "Get Out of Play", all remaining players must call "Join the Play".

Scoring for "Join the Play" players

• Players who call "Join the Play" and have any hand yakus (Te-Yaku) take points from each other player who called "Join the Play".
• Players who call "Get Out of Play" and have any hand yakus (Te-Yaku) take points from each player who called "Join the Play".
• Once all hand yakus (Te-Yaku) have been scored, all hands from players who called "Get Out of Play" are shuffled together to form the central deck.

Scoring for "Get Out of Play" players

Players who call "Get Out of Play" take points from the players who called "Join the Play" that round, based on yakus present in their starting hand.

• If the player has any hand yakus (Te-Yaku), they take their points from each player who called "Join the Play".
• If the player has all cards of a card-set yaku (Deki-Yaku) in their hand, they take their points from each player who called "Join the Play".

Playing phase

• Players play in the order in which they called "Join the Play".
• Three players take turns to play and capture cards.
  ~ The active player plays a card from their hand. If a card of the same suit is on the table, the player captures both cards.
  ~ Next, the active player flips over the top card of the central deck. If a card of the same suit is on the table, the player captures both cards.
  ~ If there are two cards of a matching suit on the table, the player chooses one to capture and the other card remains on the table.
  ~ If there are three cards of a matching suit on the table, the player capture all four cards.
  ~ If there are no cards of that suit on the table, the player captures nothing and the card remains on the table.
• When a player completes a card-set yaku (Deki-Yaku), they may choose "Stop" or "Continue playing". ~ If they choose "Stop", the playing phase ends immediately and the scoring phase begins. You will win a considerable amount of points from choosing Stop, so it is advisable in most situations. ~ If they choose "Continue playing", with the intent of creating an additional yaku before anyone else does, see this section:

Rule of "Continue playing"

When a player make a card-set yaku (Deki-Yaku) and is likely to make another card-set yaku (Deki-Yaku), they may choose to "Continue playing".
~ On BGA, if there is no possibility that another card-set yaku (Deki-Yaku) can be constructed, the game will move to the scoring phase automatically.

• When the continuing player completes their second card-set yaku (Deki-Yaku):
  ~ The continuing player scores both yakus.
• But if another player completes a card-set yaku (Deki-Yaku) first:
  ~ The continuing player's yaku is nullified.
  ~ The continuing player must pay kan to the creator of the new yaku *from their stash exclusively* (the third player does not have to pay).
• If no player completes a card-set yaku (Deki-Yaku) before the round end:
  ~ The continuing player scores only half of the points of their completed yaku.

Rule of "Hatto"

• The Hatto rule applies when a player needs only one more card to complete a card-set yaku (Deki-Yaku). [Editor's note: I have no idea when this rule would ever apply.]
  ~ If this condition is met, the player who plays the last card of the round must pay points for the winner's card-set yaku by themselves.
  ~ Note that if a player's final card is what puts them into "Hatto" mode, it does not count.

Scoring phase

• When the playing phase ends without any player completing a card-set yaku (Deki-Yaku), check if any player completed a special-scoring yaku (Tokushu-Yaku).
  ~ If a special-scoring yaku (Tokushu-Yaku) is completed, any hand yakus (Te-Yaku) paid out at the beginning of the round will be refunded.
• If no players completed any card-set yakus (Deki-Yaku) or special-scoring yakus (Tokushu-Yaku), players score the values of their captured cards this round.
  ~ Each player calculates the sum total of the scores of their captured cards. They receive (sum minus 88) mon, with gains and losses paid by the players in that round.
• If the player is entitled to score an additional 1 kan from their hand yakus (Te-Yaku) or Mizuten, it will be paid now.
• The player with the highest score in the round receives all payments from players who called "Get Out of Play". (1 kan, 2.5 kan, or 4.5 kan based on player count)
  ~ If players are tied for the highest score, the player who is earlier in turn order receives the bonus.
• The player with the highest number of points will be the dealer for the following month.

Final Scoring

At the end of 12 rounds, the player with the highest score receives the jackpot of (# of players * 5) kan, composed of the antes paid at the start of the game. If there is a tie, the winners split the jackpot equally. This is not relevant for BGA, but in the real world the winner would walk away with even more money.

Variant Rules

Game length

Half Year: Play 6 rounds (months). Each player starts the game with -3 kan.
Full Year: Play 12 rounds (months). Each player starts the game with -5 kan.

3-player game

When there are only three players in the game, the bidding phase is omitted and only the playing phase and scoring phase are conducted.

Details of yakus

List of Hand yakus (Te-Yaku)

There are two types of hand yakus: by number of Chaff cards, and by suit distribution.
~ If a player achieves both a Chaff yaku and a Suit yaku, they score them both.

Hand yakus by Chaff cards

• All Chaff (4 kan)
  ~ If a player has 7 Chaff cards (including Willows) in his/her hand the player receive 4 kan from each opponent.
  ~ The player reveals all cards in his/her hand.
  ~ If a player scores 89 points or more, he or she will receive one additional kan.
• Single Bright (4 kan)
  ~ If a player has 6 Chaff cards (including Willows) and a Bright card in his/her hand the player receive 4 kan from each opponent.
  ~ The player reveals 6 Chaff cards (including Willows) in his/her hand.
• Single Animal (3 kan)
  ~ If a player has 6 Chaff cards (including Willows) and a Animal card in his/her hand the player receive 3 kan from each opponent.
  ~ The player reveals 6 Chaff cards (including Willows) in his/her hand.
  ~ If a player scores 89 points or more, he or she will receive one additional kan.
• Single Ribbon (3 kan)
  ~ If a player has 6 Chaff cards (including Willows) and a Ribbon card in his/her hand the player receive 3 kan from each opponent.
  ~ The player reveals 6 Chaff cards (including Willows) in his/her hand.
  ~ If a player scores 89 points or more, he or she will receive one additional kan.
• Red (2 kan)
  ~ If a player has only Chaff cards (including Willows) and Ribbon cards in his/her hand the player receive 2 kan from each opponent.
  ~ The player reveals Chaff cards (including Willows) in his/her hand.
  ~ If a player scores 89 points or more during the playing phase, they will gain one additional kan.
  ~ If all seven cards in the hand are Ribbon cards, the hand yaku is also "Aka", but in this case the cards in the hand are not revealed.

Hand yakus by suit distribution

• Three (2 kan)
  ~ If the player's suit distribution in hand is 3+1+1+1+1 or 3+2+1+1, the player receives 2 kan (from those in play that round).
  ~ The player reveals the 3-card set in their hand.
  ~ If that player captures all four cards of that suit, they get one additional kan.
• Weak Three (3 kan)
  ~ If the player's suit distribution in hand is 3+1+1+1+1 or 3+2+1+1 and the three cards suit is wisteria, iris, bush clover, or three Chaff cards of paulownia the player receive 3 kans from each of the opponent players.
  ~ The player reveals the 3-card set in their hand.
  ~ If that player captures all four cards of that suit, they get one additional kan.
• Three Pairs (4 kan)
  ~ If the player's suit distribution in hand is 2+2+2+1 the player receives 4 kan from each opponent.
  ~ The player reveals the three pairs in their hand.
• Four (6 kan)
  ~ If the player's suit distribution in hand is 4+1+1+1 the player receives 6 kan from each opponent.
  ~ The player reveals the 4-card set in their hand.
• Full House (7 kan)
  ~ If the player's suit distribution in hand is 3+2+2 the player receives 7 kan from each opponent.
  ~ The player reveals all cards in their hand.
• One Two Four (8 kan)
  ~ If the player's suit distribution in hand is 4+2+1, the player receives 8 kan from each opponent.
  ~ The player reveals all cards in their hand.
• Double Threes (6 kan)
  ~ If the player's suit distribution in hand is 3+3+1, the player receives 6 kan from each opponent.
  ~ The player reveals both 3-card sets in their hand.
  ~ If the player captures all four cards of both of those suits, they get one additional kan.
• Three Weak Three (7 kan)
  ~ If the player's suit distribution in hand is 3+3+1, and one of the 3-card suits is wisteria, iris, bush clover, or three paulownia Chaff cards, the player receives 7 kan from each opponent.
  ~ The player reveals both 3-card sets in their hand.
  ~ If the player captures all four cards of both of those suits, they get one additional kan.
• Double Weak Threes (8 kan)
  ~ If the player's suit distribution in hand is 3+3+1, and both of the 3-card suits are wisteria, iris, bush clover, or three paulownia Chaff cards, the player receives 8 kan from each opponent.
  ~ The player reveals both 3-card sets in their hand.
  ~ If the player captures all four cards of both of those suits, they get one additional kan.
• Four Three (20 kan)
  ~ If the player's suit distribution in hand is 4+3, the player receives 20 kan from each opponent.
  ~ The player reveals all cards in their hand.

Other

• Mizuten
  ~ When the dealer calls "Mizuten", they receive 1 kan from each player who called "Get Out of Play" this round. ~ At the end of the round, if the player who called "Mizuten" scores 89 points or more, they receive 1 kan from each opponent at the table.

List of Card-set yaku (Deki-Yaku)

When a player acquires a card-set yaku (Deki-Yaku) during play, they may choose to "Continue Playing" to attempt to score a second yaku. Otherwise, the playing phase ends immediately and the scoring phase begins.

• Three Poetry Red Ribbons (7 kan)
  ~ When a player captures 3 Ribbon cards of pine, plum blossoms, and cherry blossoms, the player receives 7 kan from each opponent this round.
• Three Blue Ribbons (7 kan)
  ~ When a player captures 3 Ribbon cards of peony, chrysanthemum, and maple, the player receives 7 kan from each opponent.
• Seven Ribbons (10 kan)
  ~ When a player captures 7 of the 9 Ribbon cards (excluding the willow Ribbon card, which counts as a Chaff) the player receives 10 kan from each opponent.
• Four Brights (10 kan)
  ~ When a player captures 4 Bright cards of pine, cherry blossoms, eulalia, and paulownia, the player receives 10 kan from each opponent.
• Five Brights (12 kan)
  ~ When a player captures 5 Bright cards of pine, cherry blossoms, eulalia, paulownia, and willow, they receives 12 kan from each opponent.

List of special scoring yaku (Tokushu-Yaku)

During the scoring phase, players check if they scored any special-scoring yakus (Tokushu-Yaku).
~ If any player does, all hand yakus (Te-Yaku) paid at the beginning of this round will be refunded.

• 16 Chaffs (12 kan)
  ~ If a player captures 16 or more Chaff cards (including Willows), the player takes 12 kan from each opponent in that round.
  ~ For each additional Chaff card above 16 (including Willows), take an additional 2 kan.
• Double Score (10 kan)
  ~ If a player scores 168 points or more at the end of play the player receive 10 kans from each of the opponent players.
  ~ For each additional point scored the score is increased by 1 kan.
• All 88 (20 kan)
  ~ In the unlikely event that all three players have a score of exactly 88 points at the end of the playing phase, the first player in the order of play gains 20 kan.

Hanafuda cards

A Hanafuda deck consists of 12 suits, with 4 cards per suit. Here is the card-value distribution for each suit:

*All Willow (November) suit cards count as Chaff cards when forming yakus.

Card scoring points

The point values of cards captured during the playing phase are as follows: