Iroha Karuta いろは かるた is a card game played with the yuujo in Ryū Ga Gotoku:Kenzan! (龍が如く見参！). It is a card memory game, however, it relies on knowing a bit of Japanese (Kanji and Kana) to be able to beat the girls. Click on the image here and then click on "See full sized image" to see it in close up.
User:Obsessive_compulsive has devised this guide to help players pass this game: