Sudoku historical background
Like the cross-word puzzle, Sudoku is a game with a grid and a simple set of rules, generating infinite possibilities. Unlike the crossword, Sudoku doesn’t require any ‘cultural knowledge’ (general knowledge and language ability). It just requires putting numbers in cells in a logical way. Psychologists distinguish between two types of intelligence: crystallized and fluid. Crystallized intelligence depends on general knowledge and language. Fluid intelligence depends only on reasoning ability. Sudoku is a fluid intelligence puzzle.
Sudoku is Japanese for ‘only single numbers allowed’. In spite of its Japanese name the puzzle was first invented by the architect Howard Garns in the United States, appearing for the first time in May 1979 in the Dell Pencil Puzzles and Crossword Games magazine. Five years later, an editor for Niloli magazines in Japan noticed the puzzle and published it in his magazines under the name Sudoku. It then went viral in Japan. A retired New Zealand judge noticed what was going on in Japan and published some of the puzzles in the Conway Daily Sun of New Hampshire in 2004. After this, Sudoku puzzles appeared in The Times of London, and soon went viral in the UK, and then the world. Sudoku puzzles are now a permanent feature of puzzle pages in newspapers.
What is a Sudoku puzzle and how do you solve one?
A Sudoku puzzle is made up of a 9 x 9 grid, with heavy lines dividing it into nine three-by-three boxes. The challenge is to fill it with digits from 1 through 9, so that every three-by-three box, every row, and every column contains these 9 digits, without repeating – once and only once. An example of completed Sudoku puzzle is shown below to show you how this works. Notice that in each small 3×3 box, you find 1 through 9, as well as in every row and every column of the 9×9 grid.
The puzzle-maker provides some of the numbers which give the clues to be used in solving the puzzle. The fewer initial numbers that are given, the harder the puzzle. Here is a puzzle of moderate difficulty provided by puzzle master Dr. Marcel Danesi:
The solution involves logical thinking-deducing where numbers can or cannot be placed. For example in the 3rd row, the 2 spaces must be filled by either a 2 or a 4. Which number goes where? If you look at the top right 3×3 grid, you know that the middle blank cannot be a 4 because there is already a 4 lower in that column. So you can conclude that it must be a 2. Therefore the other blank must be a 4. The first blank on the 3rd row must therefore be a 2. With this extra information, you can start to figure out other numbers through similar logical reasoning. The answer to this puzzle will be given in a few days.
Benefits of Sudoku for Alzheimer’s prevention
The United States’ Alzheimer’s Association has endorsed Sudoku as a preventive brain training exercise against Alzheimer’s. Their recommendation is based on published studies, which suggest that Sudoku may help prevent dementia.
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