This is the term used in this HP.

Cell

This is the place to put 81 numbers of 9 * 9. Numbers are pre-filled in the squares. Fill in the blank squares according to the rules and proceed with the game. The game is over when all the squares are filled. You can also put a candidate number as a memo in this empty space.

Line

There are 9 squares lined up side by side. There are 9 lines in total.

Row

Nine squares lined up vertically. There are 9 rows in total.

Block

There are 9 squares of 3 * 3. There are 9 blocks in total.

Temporary placement method

It is often the case that even if you know that the correct answer is one of the multiple candidates, you cannot determine which number it is. At that time, if any of these candidates is tentatively entered and a contradiction occurs (if the rules are not met), it can be concluded that the tentatively entered candidate is incorrect, so the tentatively entered candidate is regarded as not the correct answer and is backward. Can be removed from.

Note

If the candidate you put in is correct, you may be able to solve it, so you may be shunned as an inappropriate problem, but it is still unknown whether the problem can be solved without using the temporary placement method. There is also sex. Some of the advanced problems can only be solved by the temporary placement method.

Subjunctive mood

The principle is the same as the temporary placement method, but it is a solution method that shows that a contradiction occurs even if the problem is not solved after the temporary placement. This solution has been devised by various people and published on the Internet, in magazines, and in books.

Contradiction

There are two contradictions that violate the rules

• Some numbers don't fit in rows, columns, or blocks.
• Multiple same numbers can be entered in rows, columns, and blocks.
• There are two answers.