The New Sudoku Players' Forum

[urhegyi]

It's rated 9.3 and unless there's some exotic technique it's unsolvable for me.

Code: Select all

9.4..5...25.6..1..31......8.7...9...4..26......147....7.......2...3..8.6.4.....9.

horror.png (14.93 KiB) Viewed 453 times

[m_b_metcalf]

It's rated 9.3 and unless there's some exotic technique it's unsolvable for me.

Backdoor value 1r8c6.

[denis_berthier]

This puzzle can easily be checked to be in T&E(1). It is therefore solvable by braids. As is often the case in this situation, it is also solvable by the much simpler whips.
However, as the puzzle has SER 9.3, don't expect a simple solution. Here's one in W13:

Hidden Text: Show

***********************************************************************************************
*** SudoRules 20.1.s based on CSP-Rules 2.1.s, config = W
*** Using CLIPS 6.32-r779
***********************************************************************************************
213 candidates, 1360 csp-links and 1360 links. Density = 6.02%
whip[1]: b5n5{r4c5 .} ==> r4c9 ≠ 5, r4c1 ≠ 5, r4c3 ≠ 5, r4c7 ≠ 5, r4c8 ≠ 5
biv-chain[3]: r2n9{c9 c5} - r3c4{n9 n7} - b1n7{r3c3 r2c3} ==> r2c9 ≠ 7
t-whip[4]: r1n7{c9 c4} - r1n1{c4 c5} - r1n8{c5 c2} - r2c3{n8 .} ==> r2c8 ≠ 7
whip[6]: r1n1{c4 c5} - b5n1{r4c5 r5c6} - c9n1{r5 r4} - c9n4{r4 r2} - r2c8{n4 n3} - b2n3{r2c5 .} ==> r9c4 ≠ 1
whip[8]: b1n8{r1c2 r2c3} - r2n7{c3 c6} - r3c4{n7 n9} - r2n9{c5 c9} - r6n9{c9 c7} - r6n2{c7 c8} - r6n6{c8 c1} - r4c1{n6 .} ==> r6c2 ≠ 8
whip[11]: r4c1{n6 n8} - r6c1{n8 n5} - c1n6{r6 r9} - c2n6{r7 r1} - b1n8{r1c2 r2c3} - r2n7{c3 c6} - r3c4{n7 n9} - r2n9{c5 c9} - r6c9{n9 n3} - c6n3{r6 r5} - b4n3{r5c2 .} ==> r4c3 ≠ 6
whip[13]: b9n4{r8c8 r7c7} - b3n4{r3c7 r2c9} - r2n9{c9 c5} - r3c4{n9 n7} - r3c3{n7 n6} - r1c2{n6 n8} - r2n8{c3 c6} - r6c6{n8 n3} - r5c6{n3 n1} - r7c6{n1 n6} - c2n6{r7 r6} - r4c1{n6 n8} - b5n8{r4c4 .} ==> r4c8 ≠ 4
whip[12]: r1n1{c5 c4} - r7n1{c4 c8} - r4n1{c8 c9} - r4n4{c9 c7} - b9n4{r7c7 r8c8} - r2c8{n4 n3} - b2n3{r2c5 r1c5} - r4n3{c5 c3} - b4n2{r4c3 r6c2} - c2n3{r6 r7} - c2n6{r7 r1} - r1n8{c2 .} ==> r8c5 ≠ 1
whip[12]: r1n1{c5 c4} - r7n1{c4 c8} - r4n1{c8 c9} - r4n4{c9 c7} - b9n4{r7c7 r8c8} - r2c8{n4 n3} - b2n3{r2c5 r1c5} - r4n3{c5 c3} - b4n2{r4c3 r6c2} - c2n3{r6 r7} - c2n6{r7 r1} - r1n8{c2 .} ==> r9c5 ≠ 1
whip[12]: r8n7{c8 c6} - c4n7{r9 r3} - r3c3{n7 n6} - r1n6{c2 c7} - r1n2{c7 c5} - c6n2{r3 r9} - c6n6{r9 r7} - b7n6{r7c3 r9c1} - r9n1{c1 c9} - c6n1{r9 r5} - c8n1{r5 r4} - r4n6{c8 .} ==> r1c8 ≠ 7
whip[12]: c9n4{r4 r2} - r2n9{c9 c5} - r3c4{n9 n7} - r2n7{c6 c3} - b1n8{r2c3 r1c2} - r1c4{n8 n1} - b5n1{r4c4 r5c6} - r9n1{c6 c1} - r8n1{c1 c8} - c8n7{r8 r5} - r5n8{c8 c3} - b7n8{r7c3 .} ==> r4c9 ≠ 1
whip[11]: c9n1{r5 r9} - c9n5{r9 r6} - r6n9{c9 c2} - c7n9{r6 r3} - r3c4{n9 n7} - r3c3{n7 n6} - c2n6{r1 r7} - c6n6{r7 r9} - r9n7{c6 c7} - r5c7{n7 n3} - c2n3{r5 .} ==> r5c9 ≠ 9
whip[12]: c9n5{r6 r9} - c9n1{r9 r5} - r5n5{c9 c3} - c7n5{r5 r3} - b3n9{r3c7 r2c9} - r6c9{n9 n3} - r6c6{n3 n8} - r5c6{n8 n3} - b4n3{r5c2 r4c3} - b4n2{r4c3 r6c2} - r8c2{n2 n9} - b4n9{r5c2 .} ==> r6c8 ≠ 5
whip[13]: r3n5{c8 c7} - b3n9{r3c7 r2c9} - r6c9{n9 n3} - r6c6{n3 n8} - c8n8{r6 r4} - b6n1{r4c8 r5c9} - r5c6{n1 n3} - b4n3{r5c2 r4c3} - r4n2{c3 c7} - r6c8{n2 n6} - b3n6{r1c8 r1c7} - c2n6{r1 r7} - c2n3{r7 .} ==> r5c8 ≠ 5
whip[13]: r8n4{c6 c8} - r2c8{n4 n3} - r1c9{n3 n7} - b9n7{r9c9 r9c7} - c4n7{r9 r3} - r2c6{n7 n8} - r6c6{n8 n3} - r5c6{n3 n1} - c9n1{r5 r9} - r7c8{n1 n5} - r3n5{c8 c7} - b3n9{r3c7 r2c9} - b3n4{r2c9 .} ==> r7c6 ≠ 4
whip[10]: r3c4{n9 n7} - r3c3{n7 n6} - r1c2{n6 n8} - r2n8{c3 c6} - r6c6{n8 n3} - r5c6{n3 n1} - r7c6{n1 n6} - c2n6{r7 r6} - r4c1{n6 n8} - b5n8{r4c4 .} ==> r2c5 ≠ 9
singles ==> r2c9 = 9, r4c9 = 4
whip[5]: c7n4{r7 r3} - r2c8{n4 n3} - b2n3{r2c5 r1c5} - r4n3{c5 c3} - b7n3{r7c3 .} ==> r7c7 ≠ 3
whip[7]: r6n2{c8 c2} - r8c2{n2 n9} - c3n9{r8 r5} - b4n5{r5c3 r6c1} - b4n6{r6c1 r4c1} - r4c7{n6 n3} - r6c9{n3 .} ==> r4c8 ≠ 2
whip[7]: r4c1{n8 n6} - r6c1{n6 n5} - r6c9{n5 n3} - r4c7{n3 n2} - b4n2{r4c3 r6c2} - r8c2{n2 n9} - b4n9{r5c2 .} ==> r5c3 ≠ 8
whip[8]: r6c9{n5 n3} - r1c9{n3 n7} - c7n7{r1 r9} - r9n3{c7 c3} - b4n3{r4c3 r5c2} - r5c9{n3 n1} - r5c6{n1 n8} - r6c6{n8 .} ==> r5c7 ≠ 5
whip[8]: c9n1{r9 r5} - b6n5{r5c9 r6c7} - r6c9{n5 n3} - r6c6{n3 n8} - r5c6{n8 n3} - b4n3{r5c2 r4c3} - b4n2{r4c3 r6c2} - r6n9{c2 .} ==> r9c9 ≠ 5
whip[1]: c9n5{r6 .} ==> r6c7 ≠ 5
whip[8]: r1n8{c5 c2} - r5n8{c2 c8} - r6n8{c8 c1} - r6c6{n8 n3} - r5c6{n3 n1} - r7c6{n1 n6} - c2n6{r7 r6} - r4c1{n6 .} ==> r2c6 ≠ 8
t-whip[4]: r2c8{n4 n3} - r1n3{c9 c5} - r1n1{c5 c4} - b2n8{r1c4 .} ==> r2c5 ≠ 4
whip[6]: r1n2{c8 c5} - r1n1{c5 c4} - b2n8{r1c4 r2c5} - r9c5{n8 n5} - c7n5{r9 r7} - c7n4{r7 .} ==> r3c7 ≠ 2
whip[9]: r4c1{n8 n6} - r6c1{n6 n5} - r6c9{n5 n3} - r4c8{n3 n1} - b5n1{r4c4 r5c6} - b5n8{r5c6 r6c6} - r7c6{n8 n6} - c2n6{r7 r1} - b1n8{r1c2 .} ==> r4c3 ≠ 8
whip[9]: b4n5{r5c3 r6c1} - r6c9{n5 n3} - b5n3{r6c6 r4c5} - r4c3{n3 n2} - r4c7{n2 n6} - b4n6{r4c1 r6c2} - r1n6{c2 c8} - r1n3{c8 c7} - r9n3{c7 .} ==> r5c3 ≠ 3
z-chain-rc[3]: r5c3{n9 n5} - r8c3{n5 n2} - r8c2{n2 .} ==> r7c3 ≠ 9
whip[9]: r2n8{c5 c3} - r2n7{c3 c6} - r3c4{n7 n9} - r7n9{c4 c2} - c2n8{r7 r5} - r4c1{n8 n6} - r6c1{n6 n5} - r6c9{n5 n3} - c2n3{r6 .} ==> r7c5 ≠ 8
whip[9]: r6c9{n3 n5} - b4n5{r6c1 r5c3} - c3n9{r5 r8} - r8c2{n9 n2} - b4n2{r6c2 r4c3} - b4n3{r4c3 r6c2} - c2n9{r6 r5} - r5n8{c2 c6} - r6c6{n8 .} ==> r5c8 ≠ 3
whip[9]: r6n9{c7 c2} - b4n2{r6c2 r4c3} - r4n3{c3 c5} - r6c6{n3 n8} - r5c6{n8 n1} - r7c6{n1 n6} - c2n6{r7 r1} - b1n8{r1c2 r2c3} - r2c5{n8 .} ==> r6c7 ≠ 3
whip[10]: r4c1{n6 n8} - r6c1{n8 n5} - r6c9{n5 n3} - r6c6{n3 n8} - r6c8{n8 n2} - b4n2{r6c2 r4c3} - c7n2{r4 r1} - r1n6{c7 c8} - r1n3{c8 c5} - r4n3{c5 .} ==> r6c2 ≠ 6
whip[1]: b4n6{r6c1 .} ==> r9c1 ≠ 6
biv-chain[3]: r9n6{c6 c3} - r3c3{n6 n7} - r2n7{c3 c6} ==> r9c6 ≠ 7
z-chain[5]: c3n9{r8 r5} - r5n5{c3 c9} - r6c9{n5 n3} - r6c2{n3 n2} - r8c2{n2 .} ==> r7c2 ≠ 9
whip[1]: r7n9{c5 .} ==> r8c5 ≠ 9
whip[6]: r6c6{n3 n8} - r5c6{n8 n1} - r7c6{n1 n6} - r9n6{c6 c3} - r3c3{n6 n7} - r2n7{c3 .} ==> r2c6 ≠ 3
whip[1]: c6n3{r6 .} ==> r4c5 ≠ 3
hidden-triplets-in-a-block: b2{n1 n3 n8}{r1c4 r1c5 r2c5} ==> r1c5 ≠ 2, r1c4 ≠ 7
whip[1]: r1n7{c9 .} ==> r3c7 ≠ 7, r3c8 ≠ 7
whip[1]: r1n2{c8 .} ==> r3c8 ≠ 2
biv-chain[4]: r1c9{n7 n3} - r2c8{n3 n4} - r2c6{n4 n7} - b8n7{r8c6 r9c4} ==> r9c9 ≠ 7
z-chain[5]: b1n8{r2c3 r1c2} - c2n6{r1 r7} - r7n3{c2 c8} - r2n3{c8 c5} - r2n8{c5 .} ==> r7c3 ≠ 8
biv-chain-cn[3]: c3n8{r9 r2} - c3n7{r2 r3} - c4n7{r3 r9} ==> r9c4 ≠ 8
biv-chain[3]: r9c4{n5 n7} - r3c4{n7 n9} - r7n9{c4 c5} ==> r7c5 ≠ 5
z-chain[5]: r4n3{c8 c3} - b4n2{r4c3 r6c2} - r8c2{n2 n9} - c3n9{r8 r5} - r5n5{c3 .} ==> r5c9 ≠ 3
t-whip[5]: c3n7{r3 r2} - c3n8{r2 r9} - r9n6{c3 c6} - r9n2{c6 c5} - r3n2{c5 .} ==> r3c6 ≠ 7
z-chain[6]: r4n3{c8 c3} - b4n2{r4c3 r6c2} - r8c2{n2 n9} - c3n9{r8 r5} - b4n5{r5c3 r6c1} - r6c9{n5 .} ==> r6c8 ≠ 3
z-chain[6]: r4n3{c8 c3} - b4n2{r4c3 r6c2} - r8c2{n2 n9} - r5n9{c2 c3} - b4n5{r5c3 r6c1} - r6c9{n5 .} ==> r5c7 ≠ 3
whip[5]: b9n7{r8c8 r9c7} - r5c7{n7 n9} - r5c3{n9 n5} - b7n5{r7c3 r9c1} - r9c4{n5 .} ==> r8c8 ≠ 5
whip[5]: b9n5{r7c8 r9c7} - c1n5{r9 r6} - r6c9{n5 n3} - r4n3{c7 c3} - r9n3{c3 .} ==> r7c3 ≠ 5
whip[5]: r9n6{c6 c3} - r7c3{n6 n3} - r7c2{n3 n8} - b8n8{r7c4 r9c5} - r9n2{c5 .} ==> r9c6 ≠ 1
whip[5]: r7c3{n3 n6} - c6n6{r7 r9} - r9n2{c6 c5} - r9n8{c5 c1} - r7c2{n8 .} ==> r9c3 ≠ 3
whip[1]: r9n3{c9 .} ==> r7c8 ≠ 3
whip[4]: r7c7{n4 n5} - r7c8{n5 n1} - b8n1{r7c4 r8c6} - r8n7{c6 .} ==> r8c8 ≠ 4
whip[1]: r8n4{c6 .} ==> r7c5 ≠ 4
z-chain-bn[5]: b5n1{r4c5 r5c6} - b5n3{r5c6 r6c6} - b6n3{r6c9 r4c7} - b9n3{r9c7 r9c9} - b9n1{r9c9 .} ==> r4c8 ≠ 1
whip[1]: b6n1{r5c9 .} ==> r5c6 ≠ 1
whip[1]: c6n1{r8 .} ==> r7c4 ≠ 1, r7c5 ≠ 1
singles ==> r7c5 = 9, r3c4 = 9, r2c6 = 7, r2c3 = 8, r1c2 = 6, r3c3 = 7, r2c5 = 3, r2c8 = 4, r7c7 = 4, r9c4 = 7, r8c8 = 7
naked-pairs-in-a-block: b5{r5c6 r6c6}{n3 n8} ==> r4c5 ≠ 8, r4c4 ≠ 8
whip[1]: b5n8{r6c6 .} ==> r7c6 ≠ 8, r9c6 ≠ 8
biv-chain[3]: r1n2{c7 c8} - c8n3{r1 r4} - r4c3{n3 n2} ==> r4c7 ≠ 2
stte

[Edit] Modified to include subtypes of whips. Even so, simpler patterns don't appear much in the resolution path. But, at least, you have a simpler first step (bivalue-chains[3]).