SudokuSolver Forum

There are three difficulties to choose from.
All three puzzles have the same solution.

A) Novice.
B) Apprentice (mainstream edition).
C) Master (50 Intersections, 5 Naked Pairs, 1 Naked Triplet, 1 X-Wing in g1, 1 XYZ-Wing in g1, 1 XY-Chain up to 5 links in g6). Select to view GRID numbers.
The advanced techniques are needed late in 2 different grids.



Regular Clueless Special #28A (Novice)

Rating based on required solving techniques:  Moderate

000000070090000040680090000360000000070000008000000700000009002006000000038207019
007000050000760002090000006006000080200000000003000200000003000009000870365004029
009004000000620400005070000000000007002000069090000000000200300750003600900700010
000000500007043008041000700000000800000000020000000007000900300064000000800006910
000100064700080000000005001000000007890000300007000000009000042020008500300010000
005007000410900000000000150900000020030000600000000830600400007200750000500060018
600000089000007000005080003002000700000000600030000005000020000500004000001009027
000001000009000006470050020000000000906000800041000060000300105004002000500046000
040000070008490000000800030000000010080000000079000005000000000000006002035904708



Regular Clueless Special #28B (Apprentice)

Rating based on required solving techniques:  Tough

000020076090000040080000000060000000075000008000000700000039002006000000008207010
040000050000760002090080000006000080200000300050000000000003000009000870305004029
069000730000620400005000000004000007002000069090000000000200300750003600900000010
000000500000143008000000700006000800070000020000000007010900300004000000800006910
000120064740080000000005001000000007890000300007000000009000040020008500300010000
005007000010930000000000150900000020030000600100000830600400007200750000000000018
600000089000007000405080003002000700000000600030000005300000000000004000001009027
000001004009000000470650020000000000906000800041000060060300100004000000500046000
500000070008490000000800030000000010082000000070000005400000100000036002035900008



Regular Clueless Special #28C (Master)

Rating based on required solving techniques:  Ultra Hard

000020070090070040680000000300000000070000008000000700000039002006000000008200019
007000050000760002090080006006000080200000000050000201000003000009000870305004020
009004030000620400005070000000000007002000009000000000000200300750003600900700010
000000500000143008040000700006000800000000020000000007010900300064000000800076910
000100064740080000000005001000000407890000300007000000009000042020008500300010000
305000004010930000000000150900000020030000600000000800600400000200750000000060018
600003089000000000400080003002000700000000600030000005300020000500004000001000027
000001000009000006000650020000000000900000800041000060060300100004002000500046003
040000070008490000000800030000000010080000000079000005400000000000006002235000708

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Here a mini-mini Walktrough of the Master level Regular Clueless Special #28C.

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Quis custodiet ipsos custodes?

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Børge Interestingly in Grid 1 of the Master #28C there is a unique pattern involving 9 cells giving singles to finish as an alternative to the moves you used there.

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I have 81 brain cells left, I think.

Glyn thanks for pointing out the unique pattern.

Unique patterns are not my strongest suit. I do not yet comprehend all of them completely.
I assume that the unique pattern you describe is a BUG+1?

As Hidden Text a graphical representation where the pink, green and blue cells mark the 9 cells with your deadly pattern.

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Quis custodiet ipsos custodes?

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The BUG+1 refers to an almost complete puzzle where all cells are bivalue except one trivalue cell. The candidate needed for that cell is the one which turns up 3 times in the houses to which that cell belongs. I think the principle is to avoid the unsolved cells reducing to interlocking naked sets.

This grid appears to be a more localized grouping but we are still seeking to avoid interlocking naked sets.

NOTE: The more I look at this the more I think I my have made an error, the conclusion was right but I don't think the alternative pattern wa deadly at all.

_________________
I have 81 brain cells left, I think.