 After a player's turn ends, if they made at least one yaku that turn, that player must then make a choice.They may end the hand and add the value of their yaku to their point total, or they can choose to continue playing (calling "koi-koi") in an effort to gain more points.In some versions, a player may only call koi-koi once per hand; in others, a player may call koi-koi on multiple yaku-forming turns.