Mahjong Solitaire, also called Mahjongg or Shanghai, is the tile-matching puzzle built into Windows for decades. Match pairs of free tiles to clear the stack.
Mahjong Solitaire is a single-player matching puzzle that uses a full set of 144 mahjong tiles stacked in a layered shape. The best known layout is the turtle, the one Microsoft shipped with Windows as Mahjong Titans and later Microsoft Mahjong.
No. The four-player game is a competitive tile game with scoring rules and drawing from a wall. Mahjong Solitaire only borrows the tiles. It is a pure puzzle: no opponents, no scoring hands, no luck of the draw.
The rules take ten seconds to learn, but a hard layout takes real planning. That combination — easy to start, hard to master — is why it has survived in browsers for more than twenty years.
The classic turtle layout uses all 144 tiles from a standard mahjong set.
Not always — some shuffles are unwinnable. That is why the game offers shuffle and undo.