Tu Sac (Tứ Sắc - Four Colors) is a popular Vietnamese game played with chess cards. The objective of the game is to organize a hand of cards into a combination of valid Tu Sac sets of cards through a process of melding new cards into the hand and discarding out trash cards. It is known as Si Se Pai (which also means four colors) in Chinese.
Refer to http://en.wikipedia.org/wiki/Four_Color_Cards for more information