Rules for Playing Sudoku
If you’re fond of playing puzzles, solving math problems, and think logic reasoning you can actually combine them all in solving a Sudoku puzzle.
“Su” means number in Japanese, and “doku” means single place. Although its name is based on Japanese, its origins came from Europe and America. Sudoku initially caught Japan in 1986 and gained international prominence in 2005. Sudoku was first seen in a magazine published in New York in the late 70’s by specialist puzzle publisher Dell Magazines under the name of Number Place. Its unlike other games - nothing can beat Sudoku’s challenge.
Sudoku, commonly known as Number Place, is a logic placement puzzle. The aim of the puzzle is to place the numbers from 1 to 9 in each cell of a 9×9 grid that is made up of 3×3 subgrids or regions. To start playing the game, you are given numbers in some cells referred to as “givens”. The goal of the puzzle is to fill in all of the blank cells with the numbers 1-9, with each number appearing only once in each subgrid, row and column.
Basic rules
Rules in playing the game are very simple:
- Sudoku is played over a 9×9 grid, divided in 3×3 subgrid.
- Begin the play with the given numerals from 1-9 placed in several of the grid cells.
- A number can only appear once on each row, column and subgrid
Now you fknow the basic rule for playing the game, but you’re really just starting the process of finding solutions to finish the game. There are some solution methods that can help you:
- Scanning - can be performed from the very beginning and throughout the solution process. Scanning basically has two techniques. The cross-hatching technique can identify which line in a particular region may contain a digit that can be eliminated. The second is counting the region, columns and rows to identifying missing numbers.
- Marking Up - the candidate numbers are simply written in subscript in the cell. The disadvantage of this is that some first puzzles are printed in magazines and newspapers which are usually small to accommodate many preferred numbers. For these, you can use a pattern of dots within the cell, where the position of the dot corresponds a number from 1-9. When playing a printed Sudoku, using a sharp pencil with an eraser is highly recommended.
- By Analysis - you can approach the game by either “candidate elimination or “what if”. In candidate elimination, numerals from one or more cells are eliminated and leaving just one choice. After each answer is placed, another scan can be done. You can check to see the effect of the contingencies. In the “what if” approach, a cell can be placed with two candidate numbers then a guess should be made, recorded and followed through. If it leads to a dead end, it is then replaced by the other number.
Difficulty ratings
Published Sudoku puzzles are ranked depending of rate of difficulty. The number of ‘givens’ has nothing to do with a puzzle’s difficulty. A Sudoku puzzle with a small number of givens may still be very easy for you to solve. A Sudoku puzzle with lots of givens can still be very difficult for to solve as the difficulty rate of the puzzle depends on the relevance and positioning of the given numerals rather than the number of givens placed in the grid. Computer Sudoku programs can estimate the level of difficulty of a Sudoku, based on the complexity of the techniques needed.
By playing Sudoku, the “fastest growing puzzle in the world”, you can be sure to challenge your way of thinking and have fun in the process.
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