- Code: Select all
. . 1 . 9 . 3 . .
. . . . 5 . . . .
. . . 1 4 6 . . .
. . 8 . . . 2 . .
2 . . 5 1 9 . . 6
. . 9 . . . 5 . .
. . . 3 6 1 . . .
. . . . 8 . . . .
. . 4 . 2 . 7 . .
After basics:
- Code: Select all
+-------------------+------------+--------------------+
| 4578 24568 1 | 278 9 28| 3 245678 2578 |
| 4689 24789 26 | 278 5 3 | 16 26789 124789|
| 3589 23589 2357| 1 4 6 | 89 25789 25789 |
+-------------------+------------+--------------------+
| 1357 1357 8 | 6 37 4 | 2 1379 1379 |
| 2 347 37 | 5 1 9 | 48 3478 6 |
| 13467 13467 9 | 28 37 28| 5 1347 1347 |
+-------------------+------------+--------------------+
| 5789 25789 257 | 3 6 1 | 489 24589 24589 |
| 1569 23569 256 | 4 8 7 | 16 2359 12359 |
| 368 168 4 | 9 2 5 | 7 1368 38 |
+-------------------+------------+--------------------+
This one needs some more X-chains of length 4, like SkyScraper,Turbot-crane,2-String-Kite and diagonal variants
<edit> maybe indeed 6 of them are too much for a "dogged human solver"
Here is a possible solution path with naked/hidden pairs/triples, pointing&claiming and those 6 X-chains
- Code: Select all
[1,1] r9c4=9 Naked Single
[1,2] r9c6=5 Naked Single
[2,3] r2c6=3 Hidden Single in box 2
[3,3] Naked/Hidden Pairs,Triplets,Quads | NQuad (3467)b5e1238 [HPair (28)b5e79] => (-467)r6c4 (-47)r6c6 | NQuintet (23478)b5e23789 [HSingle (6)b5e1] => (-47)r4c4 | NQuad (2378)b5e2789 [HPair (46)b5e13] => (-7)r4c6 | NPair (28)r6c46 => (-8)r6c8 (-8)r6c9 | NSingle (4)c6r4 => (-4)r8c6 | NPair (47)c6r48 => (-7)r1c6 | NTriple (489)c7r357 [HPair (16)c7r28] => (-489)r2c7 (-49)r8c7 | NPair (47)r8c46 => (-7)r8c1 (-7)r8c2 (-7)r8c3 (-4)r8c8 (-4)r8c9 | NSingle (7)r8c6 => (-7)r8c4 | NSingle (6)\4 => (-6)r1c1 (-6)r2c2 (-6)r8c8 | NSingle (4)/4 => (-4)r1c9 (-4)r2c8
[4,4] r4c4=6 Naked Single
[4,5] r4c6=4 Naked Single
[4,6] r8c4=4 Naked Single
[4,7] r8c6=7 Naked Single
[5,7] Pointing, Claiming | (7)\,b1 => (-7)r1c2 (-7)r2c1 (-7)r2c3 (-7)r3c1 (-7)r3c2 | (3)/,b7 => (-3)r8c1 (-3)r8c3 (-3)r9c2
[6,7] 2-String-Kite,SkyScraper,TurbotCrane |
Turbot Crane (8)r1c6=r6c6-r6c4=r6c6 => (-8)r1c1
[7,7] 2-String-Kite,SkyScraper,TurbotCrane |
Skyscraper (6)r2c3=r8c3-r8c7=r2c7 => (-6)r2c1 (-6)r2c8
[8,7] Naked/Hidden Pairs,Triplets,Quads | NQuintet (25789)b3e35789 [HTriple (146)b3e246] => (-2578)r1c8 (-2789)r2c9 | NQuintet (25789)/12367 [HPair (36)/89] => (-259)r8c2 (-8)r9c1
[9,7] Naked/Hidden Pairs,Triplets,Quads | NPair (36)b7e57 => (-6)r8c1 (-6)r8c3 (-6)r9c2
[10,8] r2c3=6 Hidden Single in col 3
[10,9] r8c7=6 Hidden Single in col 7
[10,10] r1c8=6 Hidden Single in col 8
[10,11] r2c9=4 Hidden Single in box 3
[10,12] r9c1=6 Hidden Single in box 7
[10,13] r8c2=3 Hidden Single in sudokuX/
[11,14] r2c7=1 Naked Single
[12,15] r6c2=6 Hidden Single in row 6
[13,15] Pointing, Claiming | (9)/,b3 => (-9)r3c8 (-9)r3c9
[14,15] 2-String-Kite,SkyScraper,TurbotCrane |
Turbot Crane (4)r5c2=r1c2-r1c1=r7c7 => (-4)r5c7
[15,16] r5c7=8 Naked Single
[16,17] r3c7=9 Naked Single
[16,18] r7c7=4 Naked Single
[17,19] r1c2=4 Hidden Single in row 1
[17,20] r5c8=4 Hidden Single in row 5
[17,21] r6c1=4 Hidden Single in row 6
[18,22] r5c2=7 Naked Single
[18,23] r5c3=3 Naked Single
[19,24] r3c1=3 Hidden Single in row 3
[19,25] r9c9=3 Hidden Single in sudokuX\
[20,25] Naked/Hidden Pairs,Triplets,Quads | NPair (15)r4c12 => (-1)r4c8 (-1)r4c9
[21,25] 2-String-Kite,SkyScraper,TurbotCrane |
2-String Kite (8)r2c1=r7c1-r9c2=r9c8 => (-8)r2c8
[22,25] 2-String-Kite,SkyScraper,TurbotCrane |
Turbot Crane (8)r1c6=r6c6-r6c4=r1c9 => (-8)r1c4
[23,25] 2-String-Kite,SkyScraper,TurbotCrane |
Turbot Crane (8)r2c2=r6c6-r6c4=r2c4 => (-8)r2c1
[24,26] r2c1=9 Naked Single
[25,27] r7c1=8 Hidden Single in col 1
[25,28] r7c2=9 Hidden Single in col 2
[25,29] r7c3=7 Hidden Single in box 7
[25,30] r9c8=8 Hidden Single in box 9
[25,31] r1c1=7 Hidden Single in sudokuX\
[25,32] r8c8=9 Hidden Single in sudokuX\
[25,33] r1c9=5 Hidden Single in sudokuX/
[25,34] r6c4=8 Hidden Single in sudokuX/
[26,35] r1c4=2 Naked Single
[26,36] r1c6=8 Naked Single
[26,37] r2c4=7 Naked Single
[26,38] r2c8=2 Naked Single
[26,39] r3c8=7 Naked Single
[26,40] r3c9=8 Naked Single
[26,41] r4c8=3 Naked Single
[26,42] r6c6=2 Naked Single
[26,43] r6c8=1 Naked Single
[26,44] r6c9=7 Naked Single
[26,45] r7c8=5 Naked Single
[26,46] r7c9=2 Naked Single
[26,47] r8c9=1 Naked Single
[26,48] r9c2=1 Naked Single
[27,49] r2c2=8 Naked Single
[27,50] r3c3=5 Naked Single
[27,51] r4c2=5 Naked Single
[27,52] r4c5=7 Naked Single
[27,53] r4c9=9 Naked Single
[27,54] r6c5=3 Naked Single
[27,55] r8c1=5 Naked Single
[27,56] r8c3=2 Naked Single
[28,57] r3c2=2 Naked Single
[28,58] r4c1=1 Naked Single