Hanafuda Koikoi is a traditional Japanese card game, known in its English version as Hanafuda Koi-Koi.

Koi-Koi (Japanese: こいこい) is a widely enjoyed card game in Japan, played with Hanafuda cards. It is one of the methods to play Hanafuda, which are traditional Japanese playing cards, and is designed for two players.

The primary objective of the game is to form combinations of cards, known as "yaku," faster than your opponent. The term "koi-koi" translates to "come on" in Japanese and is used by players who wish to continue their hand rather than cashing in their current points.

In Koi-Koi, players aim to create these special card combinations called "yaku" by accumulating cards in a point pile. Cards can be added to a player's point pile by matching them with cards on the table, either from the player's hand or drawn from the draw pile. Upon forming a yaku, a player has the option to stop and claim the points earned or to continue playing (referred to as "koi-koi") in an attempt to form additional yaku for higher scores. It's important to note that the point values on individual cards do not directly impact the score; rather, they help players assess the cards' potential in forming yaku.