Japanese Playing Card Game: "Hanafuda"

Hanafuda, Japanese for flower cards, is a  game that originated in the 1700s in Japan. There is some evidence that playing cards were first introduced into Japan by Portuguese traders

A deck consists of forty-eight cards divided into twelve suits of four cards each. Each suit represents one of the twelve months of the year which is assigned an individual plant, usually a flower. The cards are small (about 1 x 2 inches), made from stiff cardboard, and are beautifully illustrated.

Many different games can be played with a Hanafuda deck. Most involve matching the cards from the same suit for different point values. One of the most popular games played today is koi-koi, Japanese for "come on" or "let's continue". The object of the game is to form special card combinations called "yaku" from cards accumulated in a point pile. Players can gain cards in their point piles by matching cards in their hands, or drawn from the draw pile, with cards on the table. Once a yaku has been made, a player can stop to cash in points, or keep going, referred to as "koi-koi", to form additional yaku for more points.
Source:
http://boardgamegeek.com/boardgame/5451/hanafuda
http://en.wikipedia.org/wiki/Hanafuda
http://en.wikipedia.org/wiki/Koi-Koi