Place the letters A-I in the cells so that each row contains exactly one of each letter. Ditto for each column and for each region.

How To Solve a Du-Sum-Oh Puzzle


These two 9x9’s can be solved without trial and error.


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Warning! I don't think the following 9x9 puzzles can be easily solved without the use of a computer. They are interesting mathematical curiosities, having been the first non-trivial 8-hint 9x9’s discovered (as far as this author is aware). See the proof about N-1 hint puzzles for more information about this claim.


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Back to Bob’s main Du-Sum-Oh page.