# #1 What is sudoku?

Somebody says “shudoku”, others say “sudoku”. As you want. The game is still the same.

Sudoku is a crossword that you only have to write songs, but no matter how. The general, traditional sudoku is a grid of 9×9 cells, divided into nine smaller blocks of 3×3. Some cell bases are filled with numbers from 1 to 9. The task is to enter the numbers from 1 to 9  into the empty cells in a horizontal, vertical, and smaller,  3×3 blocks, exactly once . Okay, everyone knows this, but how to play it? The following few lines are for you if you do not know yet, but you want to know the game.

How do you start playing a game? Choose a sudoku crossword. Good, good, but which one you choose to have a sense of success and you can solve it all along? Start with the easy sudoku, anyway. Okay, you know, but how do you know which one is? Look for more numbers that are initially given because the easier the task is.

If you have the choice, then there is a simple way you can play it. Calculate which digit is most in the table. Each number can be up to 9, that is, up to 9 pieces of 1, max 9, 2, etc., etc.

As an example, let’s look at the above-mentioned puzzle and calculate the digits: 1 to 3, 2 to 2, 3 to 3, 4 to 2, 5 to 3, 6 to 5, 7 out of 3, out of 8 out of 5, out of 9 4. Out of the 8 and 6 are the most, that is, 5-5 pieces. Select one of the digits most of which is in the table. Let’s say the 8th. The game area is divided into 9 3×3 blocks, indicated by a bold line. Find a block that does not have the selected number. In the above case, we need to find 4 of these,

Let’s look at the blocks in a row and try to find the 8’s. We can do this by searching for a number in horizontal and vertical columns that pass through a given block and, if found, pull out (in thought) the cells within a block that belong to that row or column because there is no longer the same number. If we get the extensions and only one empty cell in the block remains untouched, we can enter the number if more, leave them blank and look at the next block.

The first such block that does not have 8 is the second block of the first row of the table. There are 8 rows across the block and two columns, so you can pull rows and columns (red marked cells). When done, you can see that only one place remains empty (marked with green) that we have not been affected, so we get 8. The first empty block is thus the next block of the table. There we go the same thing, look for the 8th possible place with pull-outs, and if only one cell left empty, write it down if not, then move on. As we can see, there are two empty spaces left here (yellowed cells), so let’s not write anything here. The next block is now below the bottom. Find your 8th place. There are 8 rows and columns across the block, so that the rows and columns are retracted (red marked cells). There is only one block where we have not been to, and this is after the 7th extras we can see that there is a blank space where we can enter the 8th. Once we went through every block where the selected number was not initially entered, but there was one we could not enter because there were two empty spaces left behind. Now, we can go back here and see if we can now search for the location of that number. If we did everything well then yes. Now, every block has been completed with 8, but if it did not, then you can return to that number after completing the table with a different number.

If you have the number you selected for the first one, then the next one, the second most number in the table, may come from. If we are going through this, then proceed in the same way. If you have all the numbers, but there is still an empty cell, you can either start it or continue it in any order.

This is one of the simplest solution logic that can be used to fill a sudokut, but there are also much faster methods. These will be discussed later.

Have a good game!