Shinro

Shinro is a logic deduction puzzle, first developed for Japanese puzzle magazines and later popularized in North America through its regular appearance in Southwest Airlines' in-flight Spirit magazine. The puzzle is played on an eight-by-eight grid that conceals twelve hidden squares called holes, and the solver's task is to locate every hole using only indirect evidence. Arrows placed around the grid point in the general direction of nearby holes, while numbers along the rows and columns state exactly how many holes each row or column contains, and the solver combines these directional and numerical clues through pure deduction to eliminate impossible squares until every hole's position is certain, without guessing. The puzzle has been compared to both Sudoku, for its grid-based logical elimination, and Minesweeper, for its concealed-square hunt. The name Shinro was coined in 2007 by the New York puzzle company Puzzability and comes from a Japanese word meaning compass bearing, a reference to the directional arrows that guide the solver toward each hidden hole.