What are the rules of sudoku?

Web sudoku is a puzzle that consists of individual squares. Most of them are 81, ie nine in the resulting square field. You have to divide the whole field imaginary into rows and columns. And then divide the whole field into nine squares of nine squares - this is usually pre-printed more heavily to make it easier for you to know the field.

How to solve sudoku

And now to those rules. Respectively, the only rule here is: There must be numbers from one to nine in each row, in each column, and in each square of nine squares, each of which must be only once.

In other words, in each row, in each column, and in each square of nine squares, you must have a complete series of digits from 1 to 9. The digits must not be missing anywhere, they must not reside anywhere. And that's all.

It is proved that the minimum number of typed digits in the input so that sudoku is unambiguously solvable is 17. If there are fewer numbers, sudoku can have more variants of solution. Sometimes the letters a - h are used instead of numbers, which helps people who are less friends with numbers than with letters.

Basically any way. We must try to create a complete series of digits from 1 to 9 (irregularly arranged) so that the digits do not repeat anywhere in a row, column or square of nine squares. So when you decide to place a number in one of the squares, you need to make sure that it does not appear elsewhere in the row, column or square.

If only one digit is missing in a row or a square or in a column, then add the one that has not yet been used. This is the easiest level of sudoku solution. When two are missing, you can often decide which of the numbers to place by using other numbers in the appropriate column or row or square.

A solution across three nine-square squares in a row or in a column below is common. For example, if you have a number one in the first column of that square, and you search in the squares below it, then the number one in the first column must not be one in the following squares. When the number one in the third square is in the middle column, the number one will necessarily be in the second square in the last column, nowhere else. Then check the rows to determine exactly where you can place the one in the selected column (and if you don't find out right from the edge, it will come to light later when you add more numbers).

How to help solve sudoku

Solving sudoku online has many techniques and tricks. You can solve by first looking for squares where it is clear which numbers to add (but this will only happen with easier sudoku variants). Then you can take the numbers from one to nine and gradually try to place them in the field. Each digit is in sudoku nine times. There is one in each column - and there are nine. The same is true for a line or square of nine squares (only the variants do not add, but intersect).

Sometimes the first time you place, for example, all nine fives, other times you will not be able to give a single number one for the first time. So when you reach nine, you can repeat the process because you have added more numbers in the meantime.

Another option is to enter. This means that when you have two options for where to place a six, for example, you will make a small six in both squares. And when you get another number in one of the squares, you immediately write the six in the other, for which it is now clear where it has its only possible location. Thanks to the inscriptions, it is as if you are half-deciphering a specific field, which will then speed up the subsequent procedure.

The most important thing is to always have an overview of the whole column, row and square with nine squares. Subsequently, the whole strip of squares in the horizontal or vertical order, which is most often worked with. If you can perceive them as a whole, it is much easier to work towards the goal based on this insight.

Where you are hesitant about placing a number, discuss the consequences of placing the number in the given place in advance. As if in your mind, take a few steps forward. If you do not encounter an obstacle, you can enter the number in the square.

But remember what number it was. If they later meet two numbers where they don't, it will probably be a mistake at this point, because few people can make enough moves in their minds in advance to think in advance of all the necessary moves to complete successfully.

This fact is quite discouraging in sudoku. For crossword puzzles, you will find an expression in the dictionary, or the letters that come out in a vertical direction will advise you. With sudoku, you can either guess where there is no clear solution, or look at the deciphered sudoku for the place you are currently doubting.

Therefore, start with simple variants, gradually create your own procedures and tricks that will suit you and make solving easier. Free Sudoku online will help you get rid of everyday worries for a while, immerse yourself in the world of pure logic and simply enjoy your moment, for example with a coffee or at bedtime.