What Is The Symmetry In Sudoku Puzzles All About?

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What Is The Symmetry In Sudoku Puzzles All About?

2 Answers

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Answer 1

Sudoku's basis lies in "Latin Squares" which have been known for thousands of years but became popular when Swiss scientist Leonhard Euler studied them. The modern version was introduced in the form of a number game called Number Place. It is often called the Rubik's cube of 21st century.

It was introduced in Japan in 1984 by publisher Nikoli using the name Sudoku. This is an abbreviation for the Japanese name "Suuji wa dokushin ni kagiru", meaning "The Numbers must be Single". They were the first ones to introduce symmetry in the puzzles.

A shape is called symmetric when it can undergo transformation without changing the way it looks. The rotational symmetry in sudoku is for aesthetic reason so that when we turn the page the position where the cells are filled remains same. The main reason for puzzles having symmetry is that they are pleasing to the eye.

Most common type of symmetry is rotational symmetry but there can be mirror symmetry as well where the axis of reflection can be vertical, horizontal or diagonal.

The eight types of symmetries possible in a sudoku puzzle are Full Dihedral, 180 Degrees Rotational, Full Rotational, Horizontal Reflection or Vertical Reflection, Horizontal & Vertical Reflection, Diagonal Reflection or Anti-Diagonal Reflection, Diagonal & Anti-Diagonal Reflection

Answer 2

Sudoku puzzles became "symmetrical" in the sense that the givens were simply distributed in what were rotationally symmetric cells. Building a Sudoku which has symmetrical givens would in effect imply positioning the undefined givens in some symmetrical pattern at the outset.

Nikoli Sudoku is actually hand-constructed, with each author being credited; you see that the givens are constantly set up in a symmetrical pattern. Nikoli is a Japanese publisher that shot to fame worldwide following the popularity of Sudoku. The Sudoku puzzles that you find printed in most of your UK newspapers are believed to be computer-generated but they do employ symmetrical givens. There are numerous fundamentally different solutions to Sudoku puzzles, after symmetries like rotation; reflection as well as re-labelling are considered.

Sudoku is essentially a logic-based number placement puzzle. The puzzle setter has to offer a partially completed grid. For more on Sudoku visit www.japaninc.com.