Ba Chō-Han [場丁半] is a simple gambling game played by spectators of a Hana-awase game at the beginning of each round, for entertainment purposes. It is attested to be played in the Tōhoku region in Japan.
The game is largely based on the traditional Japanese dice game, Chō-Han [丁半], where players bet on either “odd” or “even”, and then the dice is rolled, and the sum of the numbers is checked to see if it is odd or even.
This game is similar to the said dice game, but instead of using dice, the cards on the field [場, ba] are used instead, and the number of cards on the field that aren’t Chaff is used to indicate “odd” or “even”.
Before starting the game, decide first the bet size limit, the maximum amount a spectator can bet in each round. (This is because if the game was played for high-stakes, then the Hana-awase game, the supposed main game, would look silly in comparison.)
Set up a Hana-awase game like normal. Players playing the Hana-awase game do not participate in the game of Ba Chō-Han except for the dealer and the spectators watching the game.
Dealer deals cards as they normally would in Hana-awase, except that the cards on the field are face down.
Afterward, the dealer calls out “Odd or Even? Choose one only!”, and each spectator places their bet on either “odd” [半, han] or “even” [丁, chō].
It is not required to equalize the bets between the two sets before proceeding with the showdown. However, the dealer may need to encourage players to bet on the other set if one set has much more bets than the other.
Once all bets are finished, then proceed to showdown: All six cards of the field are flipped face-up.
The value of the field is determined by the number of non-Chaff cards on the field. This value will either be Odd (1, 3, or 5) or Even (0, 2, 4, or 6).
Spectators who have correctly bet on “Odd” or “Even” must take all players’ bets and split it between them.
Then the game of Hana-awase proceeds as normal.