Here is another interesting example of an instance of Ruud's diagonal pattern (#42 in the list of 100 provides by JPF:
http://forum.enjoysudoku.com/viewtopic.php?t=4212&postdays=0&postorder=asc&start=870).
(As I mentioned previously, this pattern is very interesting and I've already given an example of it. I'ven't studied all the 100 instances provided by JPF, but the few cases I've tried show that it allows nrczt solutions for puzzles with SER higher than usual.)
This puzzle with SER 9.4 needs nrczt-chains and lassos of length 17.1..2..3..
....4..5.
..2..6...
7..3..5..
.4..8..7.
..9.....6
9..5..4..
....2..1.
..7..1..8
***** SudoRules version 13.4 *****
1..2..3......4..5...2..6...7..3..5...4..8..7...9.....69..5..4......2..1...7..1..8
hidden-single-in-a-column ==> r8c9 = 5
nrczt12-rl-lasso n5{r9c1 r9c2} - n5{r3c2 r3c5} - n5{r6c5 r6c6} - n5{r1c6 r1c3} - n4{r1c3 r8c3} - n4{r9c1 r3c1} - n3{r3c1 r3c2} - n3{r3c5 r2c6} - n3{r8c6 r8c1} - n3{r6c1 r6c8} - n4{r6c8 r6c4} - n4{r9c4 r9c1} ==> r5c1 <> 5
nrczt16-chain n4{r9c4 r9c1} - n4{r8c3 r1c3} - n5{r1c3 r5c3} - n6{r5c3 r5c1} - n2{r5c1 r6c1} - n5{r6c1 r3c1} - n5{r9c1 r9c2} - n2{r9c2 r7c2} - n1{r7c2 r7c3} - {n1 n8}r4c3 - {n8 n1}r4c2 - {n1 n3}r6c2 - n3{r3c2 r3c5} - n3{r9c5 r9c8} - {n3 n7}r7c9 - {n7 n6}r7c5 ==> r9c4 <> 6
nrczt17-chain n4{r8c3 r1c3} - n4{r3c1 r9c1} - {n4 n9}r9c4 - n9{r8c6 r8c7} - n7{r8c7 r7c9} - {n7 n9}r1c9 - n9{r3c8 r4c8} - n9{r4c5 r3c5} - n9{r3c2 r2c2} - n9{r2c6 r5c6} - n5{r5c6 r5c3} - n5{r6c1 r3c1} - n3{r3c1 r3c2} - n7{r3c2 r1c2} - n7{r1c5 r6c5} - n1{r6c5 r4c5} - {n1 n4}r6c4 ==> r8c4 <> 4
nrczt17-chain n4{r8c3 r1c3} - n4{r3c1 r9c1} - {n4 n9}r9c4 - n9{r8c4 r8c7} - n7{r8c7 r7c9} - {n7 n9}r1c9 - n9{r3c8 r4c8} - n9{r4c5 r3c5} - n3{r3c5 r2c6} - n9{r2c6 r5c6} - n5{r5c6 r5c3} - n5{r6c1 r3c1} - n3{r3c1 r3c2} - n9{r3c2 r2c2} - n7{r2c2 r1c2} - n7{r1c5 r6c5} - n7{r6c6 r8c6} ==> r8c6 <> 4
hidden-single-in-a-block ==> r9c4 = 4
nrczt13-lr-lasso {n1 n7}r6c4 - {n7 n5}r6c5 - n5{r5c6 r1c6} - n5{r1c3 r5c3} - n6{r5c3 r5c1} - n6{r5c4 r4c5} - n1{r4c5 r3c5} - n3{r3c5 r2c6} - {n3 n8}r2c1 - {n8 n6}r2c3 - n6{r1c2 r1c8} - {n6 n4}r1c3 - n8{r1c3 r1c2} ==> r5c4 <> 1
nrczt4-chain n1{r5c9 r5c3} - n5{r5c3 r5c6} - {n5 n7}r6c5 - {n7 n1}r6c4 ==> r6c7 <> 1
nrczt16-lr-lasso {n7 n1}r6c4 - n1{r4c5 r3c5} - n3{r3c5 r2c6} - {n3 n8}r7c6 - {n8 n9}r8c6 - {n9 n5}r1c6 - {n5 n2}r5c6 - {n2 n4}r4c6 - n4{r6c6 r6c8} - n3{r6c8 r5c9} - {n3 n6}r5c1 - {n6 n8}r2c1 - {n8 n6}r2c3 - n6{r1c2 r1c8} - {n6 n4}r1c3 - n8{r1c3 r1c2} ==> r6c6 <> 7
nrczt14-chain {n7 n1}r6c4 - n1{r4c5 r3c5} - n3{r3c5 r2c6} - {n3 n8}r7c6 - {n8 n9}r8c6 - n7{r8c6 r1c6} - n5{r1c6 r1c5} - n5{r1c3 r5c3} - n5{r5c6 r6c6} - n4{r6c6 r6c8} - n3{r6c8 r5c9} - n1{r5c9 r5c7} - n9{r5c7 r5c4} - n6{r5c4 r8c4} ==> r8c4 <> 7
nrczt6-chain n3{r8c3 r8c6} - n7{r8c6 r8c7} - {n7 n2}r7c9 - n2{r2c9 r2c7} - n6{r2c7 r9c7} - {n6 n3}r7c8 ==> r7c3 <> 3
nrczt6-rl-lasso n5{r5c3 r1c3} - n4{r1c3 r8c3} - n3{r8c3 r2c3} - n3{r2c6 r3c5} - n5{r3c5 r6c5} - n5{r5c6 r5c3} ==> r5c3 <> 6
nrczt6-rl-lasso n5{r5c3 r1c3} - n4{r1c3 r8c3} - n3{r8c3 r2c3} - n3{r2c6 r3c5} - n5{r3c5 r6c5} - n5{r5c6 r5c3} ==> r5c3 <> 1
interaction row r5 with block b6 for number 1 ==> r4c9 <> 1
nrczt6-chain n3{r8c3 r8c6} - n7{r8c6 r8c7} - {n7 n2}r7c9 - n2{r2c9 r2c7} - n6{r2c7 r9c7} - {n6 n3}r7c8 ==> r7c2 <> 3
nrczt10-chain n3{r8c3 r8c6} - n7{r8c6 r8c7} - n9{r8c7 r8c4} - {n9 n6}r9c5 - n6{r9c7 r2c7} - n2{r2c7 r2c9} - {n2 n3}r7c9 - n3{r5c9 r5c3} - {n3 n8}r2c3 - {n8 n3}r2c1 ==> r9c1 <> 3
nrczt10-lr-lasso n6{r5c1 r5c4} - n6{r4c5 r7c5} - n6{r7c8 r1c8} - n6{r2c7 r8c7} - n7{r8c7 r8c6} - n9{r8c6 r8c4} - n8{r8c4 r7c6} - n3{r7c6 r2c6} - {n3 n8}r2c1 - n8{r1c2 r1c3} ==> r9c1 <> 6
nrczt15-lr-lasso n5{r9c1 r9c2} - n5{r3c2 r3c5} - n5{r1c6 r1c3} - n4{r1c3 r8c3} - n4{r8c1 r3c1} - n3{r3c1 r3c2} - n3{r8c2 r8c1} - n8{r8c1 r2c1} - n6{r2c1 r5c1} - n6{r5c4 r8c4} - {n6 n8}r8c2 - n8{r8c6 r7c6} - n8{r1c6 r1c8} - n6{r1c8 r2c7} - {n6 n3}r2c3 ==> r6c1 <> 5
nrczt10-lr-lasso {n8 n2}r6c7 - {n2 n3}r6c1 - {n3 n4}r6c8 - n4{r4c9 r4c6} - n2{r4c6 r5c6} - {n2 n6}r5c1 - {n6 n8}r2c1 - n8{r2c7 r3c7} - n8{r3c4 r8c4} - n6{r8c4 r5c4} ==> r6c2 <> 8
nrczt17-rl-lasso n5{r1c3 r5c3} - n5{r5c6 r6c6} - n5{r6c5 r3c5} - n3{r3c5 r2c6} - n3{r2c3 r8c3} - n4{r8c3 r1c3} - n6{r1c3 r1c8} - n8{r1c8 r1c6} - {n8 n7}r7c6 - {n7 n9}r8c6 - {n9 n2}r5c6 - {n2 n4}r4c6 - n4{r6c6 r6c8} - n3{r6c8 r5c9} - {n3 n6}r5c1 - n6{r5c4 r8c4} - n8{r8c4 r7c6} ==> r1c2 <> 5
nrczt17-rl-lasso {n2 n8}r6c7 - {n8 n3}r6c1 - {n3 n4}r6c8 - n4{r4c9 r4c6} - n2{r4c6 r5c6} - n2{r5c1 r9c1} - n5{r9c1 r3c1} - n4{r3c1 r8c1} - n8{r8c1 r2c1} - n6{r2c1 r5c1} - n6{r5c4 r8c4} - n8{r8c4 r3c4} - {n8 n9}r3c8 - {n9 n2}r4c8 - n2{r5c7 r2c7} - n6{r2c7 r1c8} - n8{r1c8 r3c8} ==> r6c2 <> 2nrczt12-chain n3{r2c6 r3c5} - n3{r9c5 r9c8} - n3{r7c9 r5c9} - {n3 n5}r5c3 - {n5 n1}r6c2 - n1{r6c5 r4c5} - n6{r4c5 r5c4} - {n6 n2}r5c1 - {n2 n5}r9c1 - n5{r9c2 r3c2} - n7{r3c2 r1c2} - n9{r1c2 r2c2} ==> r2c2 <> 3
nrczt17-lr-lasso n1{r3c4 r6c4} - n7{r6c4 r6c5} - n5{r6c5 r1c5} - n5{r1c3 r5c3} - {n5 n3}r6c2 - n3{r6c8 r5c9} - n1{r5c9 r2c9} - n2{r2c9 r2c7} - {n2 n8}r6c7 - {n8 n2}r6c1 - {n2 n6}r5c1 - n6{r5c4 r8c4} - {n6 n8}r8c2 - n8{r4c2 r4c3} - n8{r7c3 r7c6} - n8{r1c6 r1c8} - n6{r1c8 r2c7} ==> r3c5 <> 1interaction column c5 with block b5 for number 1 ==> r6c4 <> 1
naked-single ==> r6c4 = 7
nrczt15-chain n4{r3c1 r1c3} - n5{r1c3 r5c3} - n3{r5c3 r5c9} - n3{r6c8 r6c2} - n1{r6c2 r6c5} - n5{r6c5 r6c6} - n4{r6c6 r6c8} - n4{r3c8 r3c9} - n1{r3c9 r2c9} - n2{r2c9 r2c7} - n2{r6c7 r6c1} - {n2 n6}r5c1 - {n6 n9}r5c4 - {n9 n8}r2c4 - {n8 n3}r2c1 ==> r3c1 <> 3
nrczt10-rl-lasso n3{r3c5 r3c2} - n3{r9c2 r9c8} - n3{r6c8 r6c1} - {n3 n5}r5c3 - n5{r6c2 r9c2} - {n5 n2}r9c1 - {n2 n6}r5c1 - n6{r5c4 r4c5} - n1{r4c5 r6c5} - {n1 n5}r6c2 ==> r7c5 <> 3
nrczt10-lr-lasso n3{r3c5 r3c2} - n5{r3c2 r3c1} - n5{r9c1 r9c2} - {n5 n1}r6c2 - {n1 n5}r6c5 - {n5 n9}r1c5 - n9{r1c2 r2c2} - n7{r2c2 r1c2} - {n7 n4}r1c9 - n4{r1c3 r3c1} ==> r3c5 <> 7
nrczt9-chain n7{r7c9 r8c7} - n7{r3c7 r3c2} - n3{r3c2 r3c5} - n5{r3c5 r3c1} - n5{r9c1 r9c2} - n3{r9c2 r9c8} - n9{r9c8 r9c7} - n6{r9c7 r2c7} - n2{r2c7 r2c9} ==> r2c9 <> 7
nrczt9-lr-lasso n7{r3c7 r3c2} - n3{r3c2 r3c5} - n5{r3c5 r3c1} - n5{r9c1 r9c2} - n3{r9c2 r9c8} - {n3 n2}r7c9 - n2{r2c9 r2c7} - n6{r2c7 r1c8} - {n6 n2}r7c8 ==> r1c9 <> 7
nrczt6-chain {n4 n9}r1c9 - {n9 n8}r3c8 - {n8 n5}r3c1 - {n5 n2}r9c1 - n2{r7c2 r4c2} - {n2 n4}r4c9 ==> r3c9 <> 4
nrczt8-lr-lasso n7{r3c9 r7c9} - n3{r7c9 r5c9} - {n3 n5}r5c3 - n5{r1c3 r3c1} - {n5 n2}r9c1 - {n2 n6}r5c1 - n6{r5c4 r8c4} - {n6 n7}r7c5 ==> r3c2 <> 7
interaction row r3 with block b3 for number 7 ==> r2c7 <> 7
nrczt6-lr-lasso n7{r2c2 r2c6} - n7{r8c6 r8c7} - n6{r8c7 r9c7} - n9{r9c7 r9c8} - {n9 n3}r9c5 - n3{r3c5 r2c6} ==> r2c2 <> 6
nrczt7-rl-lasso n3{r3c5 r3c2} - n5{r3c2 r3c1} - n4{r3c1 r3c8} - {n4 n9}r1c9 - n9{r1c2 r2c2} - n7{r2c2 r2c6} - n3{r2c6 r3c5} ==> r3c5 <> 9
nrczt8-lr-lasso n2{r5c1 r9c1} - n5{r9c1 r3c1} - n4{r3c1 r3c8} - {n4 n9}r1c9 - {n9 n4}r4c9 - {n4 n9}r4c6 - n9{r4c8 r9c8} - n9{r9c5 r4c5} ==> r4c2 <> 2
interaction column c2 with block b7 for number 2 ==> r9c1 <> 2
naked-single ==> r9c1 = 5
hidden-pairs-in-a-row {n3 n5}r3{c2 c5} ==> r3c2 <> 9
hidden-pairs-in-a-block {n7 n9}{r1c2 r2c2} ==> r2c2 <> 8, r1c2 <> 8, r1c2 <> 6
hidden-pairs-in-a-row {n3 n5}r3{c2 c5} ==> r3c2 <> 8
nrczt4-chain n4{r8c3 r1c3} - n6{r1c3 r1c8} - n8{r1c8 r1c6} - n8{r7c6 r7c2} ==> r8c3 <> 8
hxyzt6-rn-chain {c8 c3}r1n6 - {c3 c6}r1n8 - {c6 c5}r1n5 - {c5 c2}r3n5 - {c2 c6}r6n5 - {c6 c8}r6n4 ==> r1c8 <> 4
nrct6-chain {n4 n9}r1c9 - {n9 n7}r1c2 - {n7 n5}r1c5 - n5{r3c5 r3c2} - n5{r6c2 r6c6} - n4{r6c6 r6c8} ==> r4c9 <> 4
naked and hidden singles ==> r1c9 = 4, r3c1 = 4, r8c3 = 4
nrc3-chain n3{r2c3 r5c3} - n5{r5c3 r1c3} - {n5 n3}r3c2 ==> r2c1 <> 3
nrczt3-chain n4{r4c8 r4c6} - n2{r4c6 r4c9} - {n2 n8}r6c7 ==> r4c8 <> 8
interaction row r4 with block b4 for number 8 ==> r6c1 <> 8
nrczt2-chain n8{r2c1 r8c1} - n8{r8c4 r3c4} ==> r2c6 <> 8
naked-triplets-in-a-row {n2 n4 n9}r4{c6 c8 c9} ==> r4c5 <> 9
nrct3-chain n3{r2c3 r5c3} - n3{r6c1 r8c1} - n8{r8c1 r2c1} ==> r2c3 <> 8
nrczt3-chain n9{r8c7 r9c8} - n9{r9c5 r1c5} - n9{r3c4 r3c9} ==> r2c7 <> 9
nrczt3-chain n6{r9c2 r4c2} - {n6 n1}r4c5 - n1{r4c3 r7c3} ==> r7c3 <> 6
nrc4-chain n7{r2c6 r2c2} - {n7 n9}r1c2 - n9{r1c5 r9c5} - n3{r9c5 r3c5} ==> r2c6 <> 3
naked and hidden singles ==> r3c5 = 3, ==> r3c2 = 5, r5c3 = 5, r2c3 = 3
naked-pairs-in-a-row {n7 n9}r2{c2 c6} ==> r2c9 <> 9, r2c4 <> 9
nrc3-chain {n9 n2}r4c9 - {n2 n1}r2c9 - n1{r5c9 r5c7} ==> r5c7 <> 9
nrczt3-chain n9{r5c6 r5c4} - n6{r5c4 r8c4} - {n6 n9}r9c5 ==> r8c6 <> 9
nrc3-chain n9{r8c4 r8c7} - n7{r8c7 r7c9} - {n7 n6}r7c5 ==> r8c4 <> 6
naked and hidden singles ==> r5c4 = 6, r4c5 = 1, r6c5 = 5, r1c6 = 5, r6c2 = 1, r7c3 = 1
interaction column c2 with block b7 for number 3 ==> r8c1 <> 3
interaction column c6 with block b8 for number 8 ==> r8c4 <> 8
naked and hidden singles
GRID 0 SOLVED. LEVEL = L17, MOST COMPLEX RULE = NRCZT17
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