Shisen-Sho

In standard Mahjong solitaire (such as Shanghai), only tiles that are unblocked on the left or right and uncovered on top can be removed. In Shisen-Sho, any two identical tiles on the board can be paired regardless of position, as long as they can be connected by a path of no more than three straight line segments (up to two turns) without other tiles blocking the path.

A standard game of Shisen-Sho uses 144 Mahjong tiles, the same count used in traditional Mahjong solitaire. The tiles are typically laid out flat on a grid rather than in the stacked, layered arrangement seen in standard Mahjong solitaire.

The name Shisen-Sho is associated with Sichuan Province in China, and the game is sometimes referred to in English as "Sichuan solitaire." It became widely popular in Japan, where it is commonly known by this Japanese rendering of the name.

If no remaining pair of identical tiles can be connected by a valid path, the game is effectively stuck or lost. Most digital implementations of Shisen-Sho provide a hint function to locate available moves or a shuffle option to rearrange remaining tiles, sometimes at a scoring penalty.