All Sudoku games are solvable. Now that's off to a great start! But the question is ― how do you win this kind of game? First and foremost, it's important to know that this is a number puzzle that can be quite tricky. So, let's start unravelling its history, fundamental concepts, and some useful techniques to give you the best gaming experience.
When Did It Begin?
Sudoku began in the 17th century. It was created by a Swiss mathematician named Leonhard Euler, describing it as a game with magic squares. The magic is in the fact that each number has its specific place that can't be changed in every particular case. The main guidelines of the game are still the same even after many centuries.
How Does the Game Work?
This number puzzle contains 81 cells that are arranged in the form of square divided into 9 columns and 9 rows. The entire grid is further divided into 9 sub-grids (3x3 boxes). As being said, each of the cells corresponds to a specific number from 1 to 9. Sounds easy, right? Yep, but the catch is ― there should be no duplications. The number must appear only once in every column, in every row, and every sub-grid.
There are different levels of Sudoku. It often starts with beginner, then easy, intermediate, and expert. The pre-filled grids mainly depend on the level of difficulty. This means that easier ones have more boxes with initial numbers.
What Are the Starting Moves?
The basic Sudoku gameplay requires you to concentrate on the empty fields and input the right numbers. While doing such, you have to eliminate the numbers that are already listed in one row, one column, and one box.
The best way to start the game is to focus on the rows, columns, or sub-grids with the highest number of pre-filled cells. For instance, if one row has all 8 numbers, this gives you an idea about what is the remaining one. Go through all of the grids because columns and rows intersect with one another. Therefore, this leaves you with more chances to complete the boxes.
If you're done with these start-up moves, you can now take the next step. If a group has two or more empty squares, then you need to check its intersecting columns and rows. At this point, you have to make use of the process of elimination. This can be done by assessing the numbers that are already listed so these will no longer be included in the possibilities for the empty squares. Following this process is vital as it will help you unlock the missing numbers, find the available spaces, and place the correct digits. Scanning two directions at a time is also a key tool when playing Sudoku. The challenge kicks in when one box can be allocated for multiple numbers. So, how do you make the right choice?
Some Strategies to Win the Game
Difficult situations arise at any part of the game. Therefore, you need to take one step at a time and not rush with inputting numbers. Here are some tips that you need to understand carefully to ensure success in every Sudoku game.
Sudoku revolves around accuracy. You can't just make unnecessary guesses. Therefore, you have to be very wary when placing the numbers. If you don't know the answer, leave it and try to fill other cells until you get an opportunity to put the right number. Remember that this specific game requires patience and logical reasoning.
Try the pencil marking
If solutions are not immediately available, making drafts can be your go-to move. Pencil marking is very helpful when solving a Sudoku game because it provides you with key candidates for an empty box. After marking the possible numbers, it will be easier to distinguish special combinations and apply some technical strategies. For example, there's the "Naked Subset", wherein two rows or columns have two same candidates that also appear on other open cells, but with other numbers. To limit the possibilities, you will remove these two candidates from those open areas because the said numbers can only appear on the two rows or columns and not anywhere else.
Another strategy is the "Naked Triple". This happens if a column or row has 3 possible numbers appearing on two cells. For example, 3, 2, and 1 are listed on two cells for column one. Then, there's another cell on column one with 6, 7, and 1. If you come across this predicament, it means that you simply remove candidates 6 and 7, leaving 1 on the cell. Therefore, the correct number to be placed on the area with pencil marks of "6, 7, 1" is 1.
Practice more challenging techniques
For higher-level Sudoku's with lesser pre-filled squares, you might need better strategies. One of the most popular ones is the X-wind. This particular method bases on the cells that encompass a rectangle. For example, all cells in rows 2 and 8 are color blue, except its 2nd and 8th cells as they are red in color. First scenario ― all cells, both blue and red colors, have number 6 as a possible candidate. Second scenario ― only the red cells (2nd and 8th cells) can use the number 6.
As a result, you have to put 6 in two of the 4 red cells. And when placing 6, they must not be on the same row. Furthermore, this eliminates all other possible 6 on the blue cells because the 2nd row must have a 6, either on the 2nd or 8th cell. This goes the same as the 8th row.
Other must-practice strategies are Swordfish and Forcing Chain. These two have unique features that you need to understand and master in detail so you can smoothly apply them during your game.
Sudoku is clearly a game that involves pure logic. Therefore, this one does not need arithmetic or any kind of guessing. So, if your answer is wrong, then get ready to start all over again! Always keep in mind that every move has an impact to the whole game. So, concentrate and weigh all your answers carefully.