Many people that I have come into contact with believe that Sudoku is not winnable, well it is. I have solved many Sudoku puzzles over the past couple of years. It’s not that Sudoku seems unwinnable; it may just be that many people do not have the patience to find strategies to solve the puzzles. That used to be me. A couple of years ago I was determined to learn to play Sudoku. Yes, it was hard at first and very time consuming, but I eventually got the hang of it. I actually use it as a stress reliever now that I am in college. When I need to take a break from homework or studying, I pull out on of my Sudoku books and complete a puzzle. I am able to solve most puzzles in under twelve minutes. For anyone interested in Sudoku, I suggest that they do not try to solve a puzzle in one day. I suggest taking it slowly and solving bits of the puzzle over the duration of multiple days, this way they will not become overwhelmed and give up all together.
Sudoku requires no calculation or arithmetic skills. It is essentially a game of placing numbers in squares, using very simple rules of logic and deduction. It can be played by children and adults and the rules are simple to learn. The objective of the game is to fill all the blank squares in a game with the correct numbers. There are three very simple constraints to follow. In a nine by nine square Sudoku game: every row of nine numbers must include all digits one through nine in any order, every column of nine numbers must include all digits one through nine in any order, and every three by three subsection of the nine by nine square must include all digits one through nine. Similarly, smaller Sudoku puzzles, such as the four by four puzzles, must have the numerals one through four in each row, column and subsection.
Every Sudoku games begin with a number of squares already filled in, and the difficulty of each game is largely a function of how many squares are filled in. The more squares that are known, the easier it is to figure out which numbers go in the open squares. As you fill in squares correctly, options for the remaining squares are narrowed and it becomes easier to fill them in. The Sudoku games on SudokuDaily.net let you check your progress as you go, to help prevent going down a wrong path.
From playing Sudoku many times I have learned a few strategies to help me solve the puzzle. First scan the rows and columns to see where a certain number might go, given the three constraints listed above. For example, the fact that a seven is required in the top right corner can be determined by first analyzing its nine square sub-regions. The only numbers missing in the region are a five and a seven. However, putting a five in the top right box would conflict with the five already in the top row and the rightmost column. The seven, on the other hand, would not conflict with any of the given numbers. Once the seven is filled in, deduction requires that only a five can go beneath it as all digits from one through nine must be represented in the region. From there, one can turn to the two remaining open boxes in the right column – these must include a two and a four as the column’s digits must represent one through nine. One of these options, placing the four beneath the one, would lead to a conflict with the four already in that horizontal row, so the only option for this box must be a two.
However, options for boxes are often not that easy to deduce. Another technique is to “pencil in” possibilities and then follow the possible solutions that emerge until a conflict is found. Often these conflicts appear after two or three numbers are penciled in, and one can return to the start and try the next option until something clicks.