A "intelligence fighting game", the players control characters walking on top of dice on the screen. If the character walks over the edge of a die, the die will topple and turn. If two dice showing 2, or three dice showing 3, or four dice showing 4 and so on, connect to each other, they will disappear into the ground.
In puzzle mode, the goal is to make all dice on the stage disappear. In Battle Mode, two players compete by running around on the screen deleting dice to earn points and defeat the other.
"Xi" is pronounced [sai], and "sai" or "saikoro" is the word for "dice" in Japanese.
The game was sequeled by Xi Jumbo (PS) and Xi-go (PS2).