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Thursday 21-Mar-2019

... by: Cenoman

WU#339 is the central symmetry of WU#338
Congratulations David, for the mockery !

Thursday 21-Mar-2019

... by: Cenoman

WU#339 has a rating S.E. 11.1 (can be qualified "hardest")
Teaching puzzle for MSLS pattern. I guess this is not by chance...
MSLS is the acronym of Multi-Sector Locked sets. A reference document has been written by David P. Bird and can be found here

For WU#339, MSLS with Home set {1,2,3,4}
20 truths in cells at intersection of rows rows A, B, D, G and columns 1, 2, 4, 7, 9
20 links: 14rA, 24rB, 13rD, 23rG, 56c1, 79c2, 58c4, 579c7, 789c9
20 eliminations: -4A6, -4B8, -1D3, -3D6, -3G5, -23G6, -9F2, -8E4, -58J4, -7C7, -79E7, -57J7, -9F9, -9H9, -78J9.

Note: the MSLS pattern can be easily spotted with pencil & paper. A few minutes looking at the givens and the pencilmarks are enough. For lazzy people, MSLS patterns are spotted by phil's solver ( previously referenced on this site.

After these 20 eliminations, the puzzle rating is downgraded to 9.4
Still hard to solve... Andrew's solver "rooks" after a few eliminations.
My own solver needs a lot of complex steps (multi-krakens)

Wednesday 20-Mar-2019

... by: Palinurus

The problem in this forum is. Some think that I have to show the complete result. Whatever it was achieved. This will deter others and lose the desire to solve the puzzle.

Wednesday 20-Mar-2019

... by: Algo

2 guesses

Cell Val Remark
B9 2 guessX2
A3 7 guessX2


Tuesday 19-Mar-2019

... by: BobW

Glad to see that Andrew and David have ignored the insults of a minority, and the weekly unsolvable is back. Like the majority, I appreciate having the Weekly Unsolvable. It's indispensable in helping me test and improve my solver program.

With additional techniques recently added to my solver, it's now able to get a logic based solution with only a single backdoor cell. For this puzzle, either of the following leads to solution: B9=2 or J7=2. However, this requires the solver program to use advanced techniques. To reduce the puzzle to being solvable with basic techniques, the following two cell backdoor is necessary: A1=6 A3=7.

Tuesday 19-Mar-2019

... by: Brutus

G = 274 356 918

Tuesday 19-Mar-2019

... by: Neil

More of the same.


Each week a new 'unsolvable' will be published and the previous will be accessible here from this archive section. If you like very tough puzzles, these are for you.
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Page created on 03-May-2011, last modified on 03-May-2011.
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