What Type of Game Sudoku is and Do you know its Resolution Methods?

What is Sudoku Game?

Sudoku is a math game that was made in the late 1970s, became popular in Japan in the 1984s. And became known internationally in 2005 when numerous newspapers start publishing Post it in your hobbies section.

The goal of the Sudoku is to fill a 9 × 9 cell grid (81 squares) divided into 3 × 3 sub-grids (also called “boxes” or “regions”) with the figures from 1 to 9 based on some numbers already arranged in some of the cells. Although colors, letters, figures could use, it agreed to use numbers for clarity. What matters is that nine different elements should not repeated in the same row, column, or sub-grid.

Sudoku is well-posed if the solution is unique, something mathematician Gary McGuire shows not possible if there is not a minimum of 17 clue figures at the beginning. The solution of Sudoku is always a Latin square. However, the reciprocal in general is not true since the Sudoku establishes the added restriction that the same number cannot repeat in a sub-grid.

History

In the 18th century, the famous Swiss mathematician Leonhard Euler made a probability system representing a series of numbers without repeating. Because of this, Euler is consider the inventor of this game.

As early as 1970, the publisher Math Puzzles and Logic Problems published a section called Number place. So this mathematical puzzle would become hobbies, although it forgot years later.

In 1984 the Japanese newspaper Monthly Nikolist made a hobby section known as Sūji wa dokushin ni kagiru (数字は独身に限る) “the numbers must be alone” (literally dokushin (独身) = “celibate, single “). It was Kaji Maki, president of Nikoli, who named it after him. The name abbreviates to Sudoku (sū = number, doku = solo).

It became known internationally in 2005 when several newspapers started publishing it as a hobby.

Rules and Terminology

Sudoku is mostly present as a 9 × 9 table, made up of 3 × 3 sub-tables called “regions” (also called “boxes” or “blocks”).

Cells already contain numbers, known as “given numbers” (or sometimes “clues or hint”). The missing one is to fill in the empty cells, with a number in each of them, so that each column, row, and region contains the numbers 1–9 only once.

Also, each number in the solution appears only once in each of the three “addresses.” Hence the “numbers must be alone” that evoke the name of the game.

Resolution Methods

Tracking

In the example above, by tracing the sevens located anywhere in the grid far and wide, the Player can remove all the empty cells in the upper left corner that cannot contain a 7. This leaves only one possible cell (checked in green).

Marked

Tracking comes to a halt when new numbers cannot discover. At this point, it needs to focus on some logical analysis. Most find it helpful to guide this analysis by marking candidate numbers in empty cells. There are two popular notations: subscripts and periods.

The Player’s numbers write in small cells. The downside is that the original puzzles publish in newspapers that usually don’t leave too much space to accommodate more than a few digits. If this notation use, solvers often create a larger copy of the puzzle and use a sharp pencil.

The second notation is a dot pattern with a dot in the upper left corner representing a 1 and a dot in the lower right corner representing a 9. This notation has the advantage that it can use in the original puzzle. Skillful placement of dots is requires because the existence of offset dots or inadvertent markings inevitably. It leads to confusion and is not easy to erase without adding further confusion.