Shisen-Sho, sometimes called “Shisen”, “Four Rivers” or simply “Rivers”, is a Japanese tile-based game that uses mahjong tiles and is similar to mahjong solitaire. The goal of the game is to match identical tiles in pairs, until each tile is removed from the playing field.

Classic Four Rivers Mahjong Connect game. Goal of the game is to remove all tiles from the board. Two of the same tiles can be removed, if they can be connected by up to three horizontal or vertical lines which pass only through empty spaces. So only two 90 degrees turns per line can be made.