Description

Sudoku is a logic based,combinatorial numberplacement puzzle. The objective is to fill a 9×9 grid with digitsso that each column, each row, and each of the nine 3×3 sub-gridsthat compose the grid (also called "boxes", "blocks", "regions", or"sub-squares") contains all of the digits from 1 to 9. The puzzlesetter provides a partially completed grid, which for a well-posedpuzzle has a unique solution.

Completed puzzles are always a type of Latin square with anadditional constraint on the contents of individual regions. Forexample, the same single integer may not appear twice in the samerow, column or in any of the nine 3×3 subregions of the 9x9 playingboard.

French newspapers featured variations of the puzzles in the 19thcentury, and the puzzle has appeared since 1979 in puzzle booksunder the name Number Place. However, the modern sudoku onlystarted to become mainstream in 1986 by the Japanese puzzle companyNikoli, under the name Sudoku, meaning single number.It firstappeared in a US newspaper and then The Times (UK) in 2004, fromthe efforts of Wayne Gould, who devised a computer program torapidly produce distinct puzzles.

Features:
- 450 unique Sudoku grilles
- 5 levels of difficulty
- intuative and simple user interface

https://en.wikipedia.org/wiki/Sudoku