Tentaizu (puzzle)

Figure 1: An example puzzle on 6x6 board with seven stars to be located

Tentaizu is a logic and algebra puzzle, in which the player locates stars in a grid by using information from neighboring cells. The solved puzzle is a star map, which names the puzzle in Japanese as "Tentaizu".

In a Tentaizu puzzle, a square grid is shown, with numbers given as clues in some of the cells. Each number indicates the number of nearby stars (in horizontally, vertically, or diagonally adjacent cells). The total number of stars to be found is also given. The stars may only appear in cells that do not have numbers, but they may be placed in cells that are not adjacent to any clue cell. The player must deduce from this information which cells contain stars, and mark each non-clue cell of the grid as being either a star or empty. Once all cells are correctly marked, the puzzle is solved.

Tentaizu appeared in Southwest Airlines' magazine Spirit in 2008–2009. It is similar to Minesweeper with the exception that Tentaizu always has a unique solution that is reachable analytically, without revealing any cells.