Anti-Knight Sudoku: Rules and Puzzle Book

Anti-knight sudoku is an enjoyable variant of a standard sudoku puzzle.

The rules are as follows:

You must place 1-9 once in each row, column and 3x3 box of the grid, as with standard sudoku.

However, there is also one new rule. The new rule is a restriction on the placement of numbers. Specifically, no number can appear a knight's move away from itself, under the rules of chess.

The diagram below explains how this works in practice: look at the 4 at the centre of the grid. As well as not being able to appear again in its row, column or box, as per standard rules, the anti-knight restriction means it cannot also appear in any of the grey squares, since these are a knight's move away. If you are unfamiliar with the rules of chess, a knight can move two squares horizontally followed by one vertically, or two vertically followed by one horizontally on any given move. This means that, depending where a digit is placed on the grid, up to eight other squares can be forbidden to contain that digit, as shown above.

anti knight sudoku rules

This knight's restriction adds some lovely logic to solving a path, and some of it can be quite subtle. You'll start to notice patterns of logical inference that can be used here that don't apply in standard sudoku that are caused by this restriction.

If you'd like to have a go at anti-knight sudoku puzzles, then you might be interested in our book that contains 100 of this fascinating variant of the standard sudoku book.

You can find out more about this book by clicking this link to our Anti-Knight Chess Sudoku Book, or by clicking the image below:

We hope you found this article interesting. Let us know if there are other sudoku variants that you'd like to hear about! Did you know that there are a range of other logic puzzles that are inspired by the moves of chess pieces? For instance king's journey and knight's tour puzzles, more information about both is available elsewhere on our site.
Date written: 30 Apr 2020

Category: sudoku | Keywords: chess | sudoku | sudoku variants

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