Shanghai II is a variant of the puzzle game solitaire mahjong. 144 mahjong tiles are arranged in rows and stacked upon each other in various patterns; the player's goal is to remove pairs of matching tiles that do not have adjacent tiles from both sides until the whole board is clear. This variant features six patterns named after animals: tiger, scorpion, monkey, snake, panther, and dragon. The player can choose to display hints or reverse any amount of moves. A mode with a time limit is available as well.
The gameplay is simple yet challenging. Players must carefully plan their moves to remove all the tiles from the board. With its unique tile-matching mechanics, Shanghai II requires strategic thinking and problem-solving skills.