Editing Latin square (section)

===Mathematical puzzles===

[[File:Ramanujan_magic_square_construction.svg|thumb|Construction of [[magic_square#Extra_constraints|Ramanujan's birthday magic square]] from a 4&times;4 Latin square with distinct diagonals and day (D), month (M), century (C) and year (Y) values, and Ramanujan's birthday example]]
The problem of determining if a partially filled square can be completed to form a Latin square is [[NP-complete]].<ref>{{cite journal | author = C. Colbourn | author-link = Charles Colbourn | title = The complexity of completing partial latin squares | journal = Discrete Applied Mathematics | volume = 8 | pages = 25–30 | year = 1984 | doi = 10.1016/0166-218X(84)90075-1| doi-access = free }}</ref>

The popular [[Mathematics of Sudoku|Sudoku]] puzzles are a special case of Latin squares; any solution to a Sudoku puzzle is a Latin square. Sudoku imposes the additional restriction that nine particular 3×3 adjacent subsquares must also contain the digits 1–9 (in the standard version). See also [[Mathematics of Sudoku]].

The more recent [[KenKen]] and [[Strimko]] puzzles are also examples of Latin squares.