Sudoku + answers

Howard Garnes, a freelance puzzle constructor and retired architect, has designed the puzzle in 1979. It was first published in New York in the late 1970s by the specialist puzzle publisher Dell Magazines in its magazine Dell Pencil Puzzles and Word Games, under the title Number Place. The puzzle was introduced in Japan by Nikoli 1984 as "Suji wa dokushin ni kagiru", which can be translated as "the numbers must be single" or "the numbers must occur only once".