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Fri, 31 Mar 2017


Isosudoku Instructions:
Here's how to play Isosudoku:
Place the numbers from 1 - n once in each row, bold-lined region and column - the columns slant forwards from left-to-right like this: /.

In addition, there are partial regions in the grid that slant backwards like this: \. Each partial region must also contain no repetition of numbers.

Hexagonal Fun With Isosudoku

Isosudoku is one of the most infrequently seen variants of sudoku, so it would not be a surprise if the majority of sudoku fans had not come across this particular puzzle type before.

The puzzle differs visually from sudoku, and quite unusually in that it uses a grid composed of hexagons, not squares, as one automatically expects with a sudoku-type puzzle.

With isosudoku puzzles, one must firstly be clear what the regions are, and then start to make use of the fact that the regions are NOT all of size 1 - n (eg they are partial regions) to help solve the puzzle.

This can take a little bit of getting used to. If one sees a region in a 6 x 6 puzzle and knows that the number 6 can only go in one place in that region, then the 6 can be placed there. When working with partial regions of course this may not be the case. For instance with a region of length five in a 6 x 6 puzzle then the values to be placed could be 1, 2, 3, 4, 5 and therefore a 6 doesn't appear anywhere (equally the digits could be 1, 3, 4, 5, 6 but the point is you don't immediately know which numbers appear in the region).

With the partial regions there are other interesting logical rules that one can use to deduce moves and make progress in the solving of the puzzle. Sometimes you will be able to work out that an integer that isn't currently present in a partial region must actually be present in that region, and so forth.

Isosudoku puzzles can require quite a bit of work to get going and placing those first few digits, and with the various extra regions to look at progress can be a little slow. For this reason they tend to only appear in specialist publications, so you probably won't come across an isosudoku puzzle in a mainstream sudoku publication!

Related puzzles

Arrow Sudoku, Calcudoku, Circle Sudoku, Consecutive Sudoku, Futoshiki, Graeco-Latin Sudoku, HyperSudoku, Irregular Sudoku, Killer Sudoku, Offset Sudoku, Outside Sudoku, Samurai Sudoku, Star Sudoku, Sudoku, Sudoku X, Toroidal Sudoku

Last updated: 16 Feb 2012

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Sample puzzle:
start Isosudoku image
Sample solution:
solution Isosudoku image

View a sample Isosudoku PDF

Play Isosudoku Puzzles:

If you're a fan of isosudoku puzzles or would like to give them a go, then they are really best solved with paper and pencil as you may need lots of pencilmarks.

You can download and print off the PDF Isosudoku Magazine at the Puzzle Magazines website.

Publish Isosudoku Puzzles:

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