suduko history and no.of squares

The modern suduko was invented by an American architect, Howard Garns, in 1979 and published by Dell Magazines under the name "Number Place".[2] It became popular in Japan in 1986, after it was published by Nikoli and given the name Sudoku, meaning single number. [3] It became an international hit in 2005
The name Sudoku means "Sūji wa dokushin ni kagiru", meaning "the numbers must be single.The difficulty of a puzzle is based on the relevance and the positioning of the given numbers rather than their quantityTypically, however, the titles are synonyms of "easy", "intermediate", and "hard". (Extremely difficult puzzles are known as "diabolical" or "evil").Competitions - The first world championship was held in Lucca, Italy from 10 to 12 March 2006.[24] The competition included numerous variants.[25] - The second world championship was held in Prague from March 28 to April 1, 2007. [26] - Hosted by renowned puzzle master Will Shortz, The Philadelphia Inquirer Sudoku National Championship was the first U.S. Sudoku Championship. The winner received $10,000 and a spot on the U.S. National Sudoku Team, which will compete in the 2008 World Sudoku Championship in India.

no.of squares in sudukoo

1. First, there are 81 individual squares.Second, there are a number of squares made up of 4 (2x2) of the smallest squares.
2. To avoid counting a square twice but to count all overlapping squares, I adopted the following recursive approach:
3. There are 4x7 = 28 unique squares with a side along the outside of the 9x9 square and an 8x8 square inside.
4. There are 4x6 = 24 unique squares with a side along the 8x8 and a 7x7 square inside.There are 4x5 = 20 unique squares with a side along the 7x7 and a 6x6 square inside.
5. There are 4x4 = 16 unique squares with a side along the 6x6 and a 5x5 square inside.There are 4x3 = 12 unique squares with a side along the 5x5 and a 4x4 square inside.
6. There are 4x2 = 8 unique squares with a side along the 4x4 and a 3x3 square inside.There are 4x1 = 4 unique squares with a side along the 3x3 and a 2x2 square inside.
7. There is 1 unique square in the centre.So there are in total 113 squares made up of 4 of the smallest squares.
8. Third, there are a number of sqaures made up of 9 (3x3) of the smallest squares:There are 4x6 = 24 unique squares with a side along the outside of the 9x9 square and an 8x8 square inside.
9. There are 4x5 = 20 unique squares with a side along the 8x8 and a 7x7 square inside.
10. There are 4x4 = 16 unique squares with a side along the 7x7 and a 6x6 square inside.
11. There are 4x3 = 12 unique squares with a side along the 6x6 and a 5x5 square inside.
12. There are 4x2 = 8 unique squares with a side along the 5x5 and a 4x4 square inside.
13. There are 4x1 = 4 unique squares with a side along the 4x4 and a 3x3 square inside.There is 1x1 square in the centre.
14. So there are in total 85 squares made up of 9 of the smallest squares.
15. Fourth, repeat the process for squares made up of 16(4x4), 25(5x5), 36(6x6), 49(7x7), 64(8x8) and finally 81(9x9) of the smallest sqaures.
16. The totals are;81 1x1 small squares113 2x285 3x361 4x441 5x525 6x613 7x75 8x81 9x9So the total number of squares is 425