JSudoku is a Sudoku solver, helper and generator written in Java. It works fine under Windows, Mac OS X and should work equally fine under Linux.

The main focus in on Killer Sudoku, but it also support vanilla Sudoku and a bunch of other variants : Sudoku X (diagonal), JigSaw, Even/Odd & the like, (non) consecutive, Greater/Less than... which may be all combined.

Added Y-Wing solver Never heard of an Y-Wing ?
Added XY-Chain & Loop solver
Added complex/killer naked triplet solver
Added support for Windoku
Automated searches of Law of Leftovers for Jigsaw. Should use fewer Grouped Wings & Fishes now.
Added combinations conflicting with 3 possibilities.
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In the previous versions, LoL were not detected by the program. You had to create / define them by hand. The program will now searches for LoL and create / define them for you.

Combinations conflicting with 3 possibilities is for Killer. It's an extension to combinations conflicting with a pair. Two examples:

1. R1C1 = {234}, Cage 9/3 in R1C234. The Cage 9/3 cannot be {234} since this would leave no candidate for R1C1.

2. Cage 8/2 in R1C12 = {17|26|35}, Cage 12/3 in R1C3456. Cage 12/3 cannot be {156|237} since this would leave no combination for Cage 8/2.

This technique is used only as a last ressort when no other easier technique can make progress. Indeed there are plenty of such conflicting combinations in a difficult killer. I found that most are useless. They do not allow to make real progress.

Added Grouped XY-Chain & Loop solver.
Added Complex/Killer XY-Chain & Loop solver.
Added Locked Cages solver. It will search for some candidate for some house locked in two sum cages and consider the implications
Added Hidden extra group solver. It’s similar to LoL and Innies, but will search for difference of N houses minus N-1 other houses resulting in exacly one house
Added Overlap solver. It will search for “simple” overlaps only up to 3 cells
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Hi Jean-Christophe,
when I down-load or try on-line it tells me version .5b3. How can I get the up-to-date one? Is there something else I have to do first?

Added Hidden extra group solver. It’s similar to LoL and Innies, but will search for difference of N houses minus N-1 other houses resulting in exacly one house
Added Overlap solver. It will search for “simple” overlaps only up to 3 cells

Don't understand these two techniques. Can you provide some assistance here please? TIA.

BTW, it's very impressive what you've managed to cram into the program in a relatively short amount of time. I would download JSudoku even if you'd just implemented one new technique, let alone 5 or more!

mhparker wrote:So the technique seems a bit redundant to me. Or are there examples that can only be solved using it?

Yes, as I said on my site, for the simplest case, one can deduce the same using several simpler techniques. But without this technique, I think it would be harder to solve The Frame or B2

Changed Design New Grid to let you control variants and the generator.
Added solver for Unique Combinations.
Added support for Non Consecutive at chess moves.
Added status bar and timer
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I have a question about your puzzle generator. Does it allow you to select a particular difficulty? For example, if I wanted a jigsaw puzzle, with LoL and x-wings, but not anything higher on the technique food chain, is this possible?

No, there is no such control of the difficulty based on the techniques used. You may generate a puzzle, then deduce all moves and inspect the techniques used.

The number of guesses gives some control, but a higher number of guesses does not always gives a harder puzzle. When the generator reports zero guesses, then the puzzle can be solved with singles only. You may set the minimum number of guesses to 1 to generate puzzles requiring some higher technique. But it could be any higher technique(s): from a simple locked candidate, to several XY chains.

Hope this helps

Here is one I made for you:
SumoCueV1=0J0=2J0=0J0=0J1=0J1=5J1=0J2=0J2=0J2=0J0=0J0=0J0=0J1=0J1=1J1=4J2=0J2=7J2=3J0=0J3=4J0=0J1=0J4=0J4=0J2=0J2=2J5=0J0=0J3=0J3=0J1=0J1=0J4=8J2=7J5=0J5=8J3=0J3=0J3=0J4=0J4=0J4=0J5=0J5=9J5=0J6=1J3=6J3=0J7=0J7=0J4=0J8=0J5=0J5=4J6=0J3=0J6=0J7=0J4=0J4=6J8=0J8=8J5=5J6=0J6=8J6=3J7=0J7=0J7=0J8=0J8=0J8=0J6=0J6=0J6=9J7=0J7=0J7=0J8=8J8=0J8