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Monday Mutant 5: Crowd Nine (consecutive)

Monday Mutants is a series in which I will attempt to experiment with "mutant" puzzles. These could be existing puzzle types with an unusual change in the rules, hybrids combining elements from multiple puzzle types, or puzzle types neither invented nor popularized by Nikoli.
In this Crowd Nine puzzle, if a pair of horizontally or vertically adjacent cells contains two consecutive numbers, there will be a circle between them, and if a pair of horizontally or vertically adjacent cells contains two numbers that are not consecutive, there will not be a circle between them. The rules are otherwise unchanged.


Ray said...

Nice puzzle Grant! Is this a format that you've seen before?

Grant Fikes said...

Ray: I have seen this variant before, although I'd never attempted to solve one, and I've never seen one in a Nikoli publication. (In fact, the only Sudoku puzzles I've seen by Nikoli are traditional 9x9, 16x16, and 25x25 puzzles.)

TheSubro said...

While I think I have seen this variation before, I thought the even / odd runs through the middles was a very nice touch. Nice puzzle.



Jonah said...

There was one of these in the Sudoku Cup recently, no? But I like this one better, especially the middle row. I also like that it appears unsolvable at first glance, since without the nonconsecutive constraint you could switch the fourth and sixth rows or columns.

Anyway, fun solve, if a bit on the easy side compared to previous mutants.

Speaking of which, is there a chance some of these could become recurring formats? I especially liked the Inequality Polyominous.

Grant Fikes said...

Thanks for the feedback, TheSubro and Jonah! :)

Jonah: I don't really follow the Sudoku Cup, nor any puzzle competition, but I've seen this variation before, and it seems to be pretty common. Thomas Snyder has even made a few, it seems.

As for whether a variation will recur, that depends entirely on my inspiration. Sometimes, a variant might not offer enough possibilities to justify making or solving it more than once or twice.

Anonymous said...

@ Jonah
There were two puzzles of this type in my recent SudokuCup - one "Consecutive" and one "Nonconsecutive" but both with the same rule set. Grant's puzzle here is much closer to a nonconsecutive in that there are only 4 cells with boundaries demarked which is much less than a typical consecutive. Its actually a fairly common type at the world sudoku championship and in foreign sudoku magazines. Wei-Hwa Huang and I constructed ~18 for our book Mutant Sudoku if you want to find more.

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