For millennia, people have been attracted to things that annoyed them. Riddles, word and number puzzles: if they involved intense thought, they were adored. The 1970s saw the widespread love affair (perhaps a little love-hate) with a simple block containing rotating smaller square blocks of different colors called “Rubik’s Cube”. This year’s head-scratching, hair-pulling, and downright addictive game of choice is a Japanese creation by the name of Sudoku.
Like the vast majority of great Sudoku puzzles, it looks seemingly benign, a simple grid of nine squares, each containing nine smaller squares (equivalent to eighty-one small squares in all). The nine large (“mother”) squares are generally considered to belong to one of three puzzle grids known as regions. Each of the eighty-one small squares contains, or will contain when completed, a numeral between the numbers one and nine.
Even the rules of this game, which hit the mainstream in Japan in 1986, seem relatively straightforward. To “win” in Sudoku, you must fill in every region, column and row of the grid, there can be no blank spaces. However, the difficulty begins to factor in when you take into account the rule that each of these areas can only contain the number (one through nine) once. Some of the squares already contain numbers, these are known as “dice”, it is the player’s job to fill in the empty spaces, while adhering to the “one occurrence” rule for each number in each of the three directions of the puzzle. .
Interestingly, the numbers are only used for convenience as they have no mathematical relationship to the game itself*. They do not have to add up to a sum or occur in a particular set of patterns. Instead of numbers the puzzle can contain shapes, colors, symbols, whatever, as long as the same rule can be applied (that each one only appears once in each area of the puzzle). Perhaps the appeal of Sudoku lies in the fact that it looks so easy, what’s so hard about completing a few squares, right? One try at this game, though, and all but the most seasoned logistics puzzle pros will find themselves a little over their heads. This is not to say that the game cannot be completed, on the contrary, it can be, and after a while Sudoku “pros” can complete a puzzle in a matter of minutes. But this requires work, a lot of work, study and devotion to this unique Japanese square.
The world has certainly jumped on the Sudoku bandwagon, its popularity spawning websites (often featuring many free puzzles of varying degrees of difficulty) and regular Sudoku puzzles in many magazines and newspapers, even Sudoku software! With a crossword-like appearance and strategic maneuvers reminiscent of chess, it’s no wonder Sudoku has sprung from Japan and become an international obsession.
*Actually, Sudoku has a mathematical principle behind it known as “complexity theory”, which classifies Sudoku as an “NP-complete (Non-Deterministic Polynomial Time) puzzle (or problem).” The “NP” means that a puzzle/problem with this rating is the most difficult problem of its type to solve. It is a very complex mathematical form that does not yet have a definitive arithmetic solution for each and every Sudoku grid.