Analysis of zz-www.sudokuoftheday.co.uk-20060327-absurd-base.sdk

Contents

Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Mar&YEAR=2006

level: medium

Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Mar&YEAR=2006

position: 96.8.2.4...4.5...2...9..7.62.....87.8492............6..9.5.....5....9.1...142...7 initial

Autosolve

position: 96.8.2.4...4.5...2...9..7.62.6..587.8492...........26.49.5..62.5....941.6.142...7 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B2: 1,3 => CTR => B2: 7,8
* DIS # E3: 1,3 => CTR => E3: 4
* DIS # A6: 1,3 => CTR => A6: 7
* PRF # F2: 6,7 => SOL
* DIS # F2: 1,3 => CTR => F2: 6,7
* DIS # B3: 5,8 => CTR => B3: 2
* DIS # A6: 1,3 => CTR => A6: 7
* DIS # B6: 1,3 => CTR => B6: 5,7
* DIS # B2: 1,3 => CTR => B2: 7,8
* DIS # E6: 4,9 => CTR => E6: 8
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # E8: 3,8 => SOL
* PRF # F2: 6,7 => SOL
* DIS # F2: 1,3 => CTR => F2: 6,7
* DIS # A6: 1,3 => CTR => A6: 7
* DIS # B6: 1,3 => CTR => B6: 5,7
* DIS # E6: 9 => CTR => E6: 4,8
* DIS # E6: 4,9 => CTR => E6: 8
* PRF # C7: 3,8 => SOL
* DIS # C7: 7 => CTR => C7: 3,8
* DIS # B8: 3,8 => CTR => B8: 2,7
* DIS # C8: 3,8 => CTR => C8: 2,7
* DIS # B2: 1,7 => CTR => B2: 3,8
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # E8: 3,8 => SOL
* DIS # E7: 3,8 => CTR => E7: 1,7
* DIS # F7: 3,8 => CTR => F7: 1,7
* PRF # E8: 3,8 => SOL
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # C7: 3,8 => SOL
* DIS # C7: 7 => CTR => C7: 3,8
* DIS # E7: 3,8 => CTR => E7: 1,7
* DIS # F7: 3,8 => CTR => F7: 1,7
* DIS # B8: 3,8 => CTR => B8: 2,7
* DIS # C8: 3,8 => CTR => C8: 2,7
* PRF # E8: 3,8 => SOL
* DIS # E8: 6,7 => CTR => E8: 3,8
* CNT  37 HDP CHAINS /  67 HYP OPENED

See Appendix: Full HDP Chains for full list of HDP chains.

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* DIS # B2: 1,3 => CTR => B2: 7,8
* DIS B2: 7,8 # A2: 7 => CTR => A2: 1,3
* DIS B2: 7,8 + A2: 1,3 # E3: 1,3 => CTR => E3: 4
* PRF B2: 7,8 + A2: 1,3 + E3: 4 # F2: 6,7 => SOL
* STA B2: 7,8 + A2: 1,3 + E3: 4 + F2: 6,7
* CNT   4 HDP CHAINS /   6 HYP OPENED

See Appendix: Full HDP Chains for full list of HDP chains.

Details

Positions

96.8.2.4...4.5...2...9..7.62.....87.8492............6..9.5.....5....9.1...142...7 initial
96.8.2.4...4.5...2...9..7.62.6..587.8492...........26.49.5..62.5....941.6.142...7 autosolve
967812345384756192125943786216395874849267531753184269498571623572639418631428957 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (22)
A3: 1,3
D2: 6,7
I1: 1,5
H3: 5,8
B4: 1,3
D4: 1,3
E4: 4,9
E5: 6,7
F5: 6,7
D6: 1,3
F6: 4,8
I4: 4,9
H5: 3,5
I5: 1,5
I6: 4,9
B9: 3,8
D8: 6,7
F9: 3,8
I7: 3,8
I8: 3,8
G9: 5,9
H9: 5,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D4,D6: 1.. / D4 = 1  =>  0 pairs (X) / D6 = 1  => 20 pairs (_)
G5,I5: 1.. / G5 = 1  => 23 pairs (_) / I5 = 1  => 21 pairs (_)
E7,F7: 1.. / E7 = 1  => 25 pairs (_) / F7 = 1  =>  0 pairs (*)
B4,D4: 1.. / B4 = 1  => 20 pairs (_) / D4 = 1  =>  0 pairs (X)
I1,I5: 1.. / I1 = 1  => 23 pairs (_) / I5 = 1  => 21 pairs (_)
B3,C3: 2.. / B3 = 2  => 24 pairs (_) / C3 = 2  =>  0 pairs (X)
B8,C8: 2.. / B8 = 2  =>  0 pairs (X) / C8 = 2  => 24 pairs (_)
B3,B8: 2.. / B3 = 2  => 24 pairs (_) / B8 = 2  =>  0 pairs (X)
C3,C8: 2.. / C3 = 2  =>  0 pairs (X) / C8 = 2  => 24 pairs (_)
D4,D6: 3.. / D4 = 3  => 20 pairs (_) / D6 = 3  =>  0 pairs (X)
G5,H5: 3.. / G5 = 3  => 18 pairs (_) / H5 = 3  => 23 pairs (_)
I7,I8: 3.. / I7 = 3  => 21 pairs (_) / I8 = 3  => 23 pairs (_)
B4,D4: 3.. / B4 = 3  =>  0 pairs (X) / D4 = 3  => 20 pairs (_)
B9,F9: 3.. / B9 = 3  => 18 pairs (_) / F9 = 3  =>  0 pairs (X)
H2,H5: 3.. / H2 = 3  => 18 pairs (_) / H5 = 3  => 23 pairs (_)
E3,F3: 4.. / E3 = 4  => 19 pairs (_) / F3 = 4  =>  0 pairs (X)
I4,I6: 4.. / I4 = 4  => 20 pairs (_) / I6 = 4  =>  0 pairs (X)
E4,I4: 4.. / E4 = 4  =>  0 pairs (X) / I4 = 4  => 20 pairs (_)
F3,F6: 4.. / F3 = 4  =>  0 pairs (X) / F6 = 4  => 19 pairs (_)
B6,C6: 5.. / B6 = 5  => 24 pairs (_) / C6 = 5  =>  0 pairs (X)
G9,H9: 5.. / G9 = 5  => 24 pairs (_) / H9 = 5  => 19 pairs (_)
B3,B6: 5.. / B3 = 5  =>  0 pairs (X) / B6 = 5  => 24 pairs (_)
I1,I5: 5.. / I1 = 5  => 21 pairs (_) / I5 = 5  => 23 pairs (_)
D2,F2: 6.. / D2 = 6  =>  0 pairs (X) / F2 = 6  =>  0 pairs (_)
E5,F5: 6.. / E5 = 6  =>  0 pairs (*) / F5 = 6  =>  0 pairs (X)
D8,E8: 6.. / D8 = 6  =>  0 pairs (*) / E8 = 6  =>  0 pairs (X)
D2,D8: 6.. / D2 = 6  =>  0 pairs (X) / D8 = 6  =>  0 pairs (_)
E5,E8: 6.. / E5 = 6  =>  0 pairs (*) / E8 = 6  =>  0 pairs (X)
F2,F5: 6.. / F2 = 6  =>  0 pairs (*) / F5 = 6  =>  0 pairs (X)
E5,F5: 7.. / E5 = 7  =>  0 pairs (X) / F5 = 7  =>  0 pairs (_)
C1,E1: 7.. / C1 = 7  =>  0 pairs (*) / E1 = 7  =>  0 pairs (X)
A2,A6: 7.. / A2 = 7  =>  0 pairs (X) / A6 = 7  => 26 pairs (_)
D2,D8: 7.. / D2 = 7  =>  0 pairs (*) / D8 = 7  =>  0 pairs (X)
H2,H3: 8.. / H2 = 8  =>  0 pairs (X) / H3 = 8  => 21 pairs (_)
E6,F6: 8.. / E6 = 8  => 19 pairs (_) / F6 = 8  =>  0 pairs (X)
I7,I8: 8.. / I7 = 8  => 23 pairs (_) / I8 = 8  => 21 pairs (_)
B2,H2: 8.. / B2 = 8  => 21 pairs (_) / H2 = 8  =>  0 pairs (X)
B9,F9: 8.. / B9 = 8  =>  0 pairs (X) / F9 = 8  => 18 pairs (_)
G2,H2: 9.. / G2 = 9  => 24 pairs (_) / H2 = 9  => 19 pairs (_)
E4,E6: 9.. / E4 = 9  => 20 pairs (_) / E6 = 9  =>  0 pairs (X)
I4,I6: 9.. / I4 = 9  =>  0 pairs (X) / I6 = 9  => 20 pairs (_)
G9,H9: 9.. / G9 = 9  => 19 pairs (_) / H9 = 9  => 24 pairs (_)
E4,I4: 9.. / E4 = 9  => 20 pairs (_) / I4 = 9  =>  0 pairs (X)
E6,I6: 9.. / E6 = 9  =>  0 pairs (X) / I6 = 9  => 20 pairs (_)
G2,G9: 9.. / G2 = 9  => 24 pairs (_) / G9 = 9  => 19 pairs (_)
H2,H9: 9.. / H2 = 9  => 19 pairs (_) / H9 = 9  => 24 pairs (_)
* DURATION: 0:01:06.208173  START: 21:56:36.498649  END: 21:57:42.706822 2019-04-30
* CP COUNT: (46)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B4,B9,D2,D4,D6,D8,E4,E5,F5,F6,F9,G9,H3,H5,H9,I1,I4,I5,I6,I7,I8)
* 96.8.2.4...4.5...2...9..7.62.6..587.8492...........26.49.5..62.5....941.6.142...7
* PAIR A3: 1,3 BLK 1
A2: 1,3,7                                # reduction candidate for 1,3
A2: 1,3                                  # 26 pairs
B2: 1,3,7,8                              # reduction candidate for 1,3
B2: 1,3 => CTR
* 965872.4...4.5..82...9..7562.6..587.8492...35.5....26.49.5..62.5726.941.6.142.597
B2: 7,8                                  # 24 pairs
* PAIR A3: 1,3 ROW 3
E3: 1,3,4                                # reduction candidate for 1,3
E3: 1,3 => CTR
* 965872341..4651.82..89.47562.6..587.8492...35.5...826.49.5..62.5.2..941.681423597
E3: 4                                    # 19 pairs
F3: 1,3,4                                # reduction candidate for 1,3
F3: 1,3                                  # 19 pairs
* PAIR A3: 1,3 COL A
A6: 1,3,7                                # reduction candidate for 1,3
A6: 1,3 => CTR
* 96.8.2.4.7.465...2...9..7.62.6..587.8492.6.........26.49.5.762.5....941.6.142...7
A6: 7                                    # 26 pairs
* PAIR D2: 6,7 BLK 2
F2: 6,7,1,3                              # reduction candidate for 6,7
F2: 6,7 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
F2: 1,3 => CTR
* 96.8.2.4...465...2...9..7.62.6..587.8492.6.........26.49.5.762.5....941.6.142...7
* PAIR I1: 1,5 BLK 3
G1: 1,5,3                                # reduction candidate for 1,5
G1: 3                                    # 26 pairs
G1: 1,5                                  # 26 pairs
* PAIR H3: 5,8 ROW 3
B3: 5,8,2                                # reduction candidate for 5,8
B3: 5,8 => CTR
* 96.872.4...465...2..29..7.62.6..587.84926..........26.49.5..62.52...941.6.142...7
B3: 2                                    # 24 pairs
C3: 5,8,2                                # reduction candidate for 5,8
C3: 5,8                                  # 24 pairs
* PAIR B4: 1,3 BLK 4
A6: 1,3,7                                # reduction candidate for 1,3
A6: 1,3 => CTR
* 96.8.2.4.7.465...2...9..7.62.6..587.8492.6.........26.49.5.762.5....941.6.142...7
A6: 7                                    # 26 pairs
B6: 1,3,5,7                              # reduction candidate for 1,3
B6: 1,3 => CTR
* 96.8.2.4...4.5...2.529..7862.6..587.8492.......5...26.49.5..62.52...941.6.142...7
B6: 5,7                                  # 23 pairs
* PAIR B4: 1,3 COL B
B2: 1,3,7,8                              # reduction candidate for 1,3
B2: 1,3 => CTR
* 965872.4...4.5..82...9..7562.6..587.8492...35.5....26.49.5..62.5726.941.6.142.597
B2: 7,8                                  # 24 pairs
* PAIR E4: 4,9 BLK 5
E6: 4,9,8                                # reduction candidate for 4,9
E6: 4,9 => CTR
* 965872341..4651.82..89.47562.6..587.8492...35.5...826.49.5..62.5.2..941.681423597
E6: 8                                    # 19 pairs
* PAIR E5: 6,7 COL E
E8: 6,7,3,8                              # reduction candidate for 6,7
E8: 6,7 => CTR
* 9678.2.4...4.5...2...9..7.62.6..587.8492.....7.....26.49.5..62.5....941.6.142...7
E8: 3,8 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
* PAIR F5: 6,7 COL F
F2: 6,7,1,3                              # reduction candidate for 6,7
F2: 6,7 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
F2: 1,3 => CTR
* 96.8.2.4...465...2...9..7.62.6..587.8492.6.........26.49.5.762.5....941.6.142...7
* PAIR D6: 1,3 ROW 6
A6: 1,3,7                                # reduction candidate for 1,3
A6: 1,3 => CTR
* 96.8.2.4.7.465...2...9..7.62.6..587.8492.6.........26.49.5.762.5....941.6.142...7
A6: 7                                    # 26 pairs
B6: 1,3,5,7                              # reduction candidate for 1,3
B6: 1,3 => CTR
* 96.8.2.4...4.5...2.529..7862.6..587.8492.......5...26.49.5..62.52...941.6.142...7
B6: 5,7                                  # 23 pairs
* PAIR F6: 4,8 BLK 5
E6: 4,8,9                                # reduction candidate for 4,8
E6: 9 => CTR
* 965872341..4651.82..89.47562.6.458798492...35.5..9826449.5..62.5.2..941.681423597
E6: 4,8                                  # 20 pairs
* PAIR H5: 3,5 BLK 6
G5: 3,5,1                                # reduction candidate for 3,5
G5: 1                                    # 23 pairs
G5: 3,5                                  # 21 pairs
* PAIR I5: 1,5 BLK 6
G5: 1,5,3                                # reduction candidate for 1,5
G5: 1,5                                  # 23 pairs
G5: 3                                    # 18 pairs
* PAIR I6: 4,9 ROW 6
E6: 4,9,8                                # reduction candidate for 4,9
E6: 4,9 => CTR
* 965872341..4651.82..89.47562.6..587.8492...35.5...826.49.5..62.5.2..941.681423597
E6: 8                                    # 19 pairs
* PAIR B9: 3,8 BLK 7
C7: 3,8,7                                # reduction candidate for 3,8
C7: 3,8 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
C7: 7 => CTR
* 96.872.4...465...2...9..7.62.6..587.84926..........26.4975..62.5....941.6.142...7
B8: 3,8,2,7                              # reduction candidate for 3,8
B8: 3,8 => CTR
* 96.8.2.4..7465..82.289..7562163.587.8492.6.357531..26.4975..62.5.276941.6.142.597
B8: 2,7                                  # 23 pairs
C8: 3,8,2,7                              # reduction candidate for 3,8
C8: 3,8 => CTR
* 96.872.4...465...2..29..7.62163.587.8492...........26.4975..62.528..9413631428..7
C8: 2,7                                  # 23 pairs
* PAIR B9: 3,8 COL B
B2: 3,8,1,7                              # reduction candidate for 3,8
B2: 1,7 => CTR
* 965872341..465.982...9..7562.6..587.84926..35.5....26.49.5..62.5....941.6.142.597
B2: 3,8                                  # 24 pairs
* PAIR D8: 6,7 BLK 8
E8: 6,7,3,8                              # reduction candidate for 6,7
E8: 6,7 => CTR
* 9678.2.4...4.5...2...9..7.62.6..587.8492.....7.....26.49.5..62.5....941.6.142...7
E8: 3,8 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
* PAIR F9: 3,8 BLK 8
E7: 3,8,1,7                              # reduction candidate for 3,8
E7: 3,8 => CTR
* 96.872.4...4653..2...9..7.62.6..587.8492...........26.4975.162.5....941.6.142...7
E7: 1,7                                  # 23 pairs
F7: 3,8,1,7                              # reduction candidate for 3,8
F7: 3,8 => CTR
* 96.872.4...465...2...9..7.62.6..587.84926..........26.49751.62.5....941.6.142...7
F7: 1,7                                  # 23 pairs
E8: 3,8,6,7                              # reduction candidate for 3,8
E8: 3,8 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
E8: 6,7 => CTR
* 9678.2.4...4.5...2...9..7.62.6..587.8492.....7.....26.49.5..62.5....941.6.142...7
* PAIR I7: 3,8 ROW 7
C7: 3,8,7                                # reduction candidate for 3,8
C7: 3,8 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
C7: 7 => CTR
* 96.872.4...465...2...9..7.62.6..587.84926..........26.4975..62.5....941.6.142...7
E7: 3,8,1,7                              # reduction candidate for 3,8
E7: 3,8 => CTR
* 96.872.4...4653..2...9..7.62.6..587.8492...........26.4975.162.5....941.6.142...7
E7: 1,7                                  # 23 pairs
F7: 3,8,1,7                              # reduction candidate for 3,8
F7: 3,8 => CTR
* 96.872.4...465...2...9..7.62.6..587.84926..........26.49751.62.5....941.6.142...7
F7: 1,7                                  # 23 pairs
* PAIR I8: 3,8 ROW 8
B8: 3,8,2,7                              # reduction candidate for 3,8
B8: 3,8 => CTR
* 96.8.2.4..7465..82.289..7562163.587.8492.6.357531..26.4975..62.5.276941.6.142.597
B8: 2,7                                  # 23 pairs
C8: 3,8,2,7                              # reduction candidate for 3,8
C8: 3,8 => CTR
* 96.872.4...465...2..29..7.62163.587.8492...........26.4975..62.528..9413631428..7
C8: 2,7                                  # 23 pairs
E8: 3,8,6,7                              # reduction candidate for 3,8
E8: 3,8 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
E8: 6,7 => CTR
* 9678.2.4...4.5...2...9..7.62.6..587.8492.....7.....26.49.5..62.5....941.6.142...7
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060327-absurd-base-pr-000.dot
* REASONING
* DIS # B2: 1,3 => CTR => B2: 7,8
* DIS # E3: 1,3 => CTR => E3: 4
* DIS # A6: 1,3 => CTR => A6: 7
* PRF # F2: 6,7 => SOL
* DIS # F2: 1,3 => CTR => F2: 6,7
* DIS # B3: 5,8 => CTR => B3: 2
* DIS # A6: 1,3 => CTR => A6: 7
* DIS # B6: 1,3 => CTR => B6: 5,7
* DIS # B2: 1,3 => CTR => B2: 7,8
* DIS # E6: 4,9 => CTR => E6: 8
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # E8: 3,8 => SOL
* PRF # F2: 6,7 => SOL
* DIS # F2: 1,3 => CTR => F2: 6,7
* DIS # A6: 1,3 => CTR => A6: 7
* DIS # B6: 1,3 => CTR => B6: 5,7
* DIS # E6: 9 => CTR => E6: 4,8
* DIS # E6: 4,9 => CTR => E6: 8
* PRF # C7: 3,8 => SOL
* DIS # C7: 7 => CTR => C7: 3,8
* DIS # B8: 3,8 => CTR => B8: 2,7
* DIS # C8: 3,8 => CTR => C8: 2,7
* DIS # B2: 1,7 => CTR => B2: 3,8
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # E8: 3,8 => SOL
* DIS # E7: 3,8 => CTR => E7: 1,7
* DIS # F7: 3,8 => CTR => F7: 1,7
* PRF # E8: 3,8 => SOL
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # C7: 3,8 => SOL
* DIS # C7: 7 => CTR => C7: 3,8
* DIS # E7: 3,8 => CTR => E7: 1,7
* DIS # F7: 3,8 => CTR => F7: 1,7
* DIS # B8: 3,8 => CTR => B8: 2,7
* DIS # C8: 3,8 => CTR => C8: 2,7
* PRF # E8: 3,8 => SOL
* DIS # E8: 6,7 => CTR => E8: 3,8
* CNT  37 HDP CHAINS /  67 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B4,B9,D2,D4,D6,D8,E4,E5,F5,F6,F9,G9,H3,H5,H9,I1,I4,I5,I6,I7,I8)
* 96.8.2.4...4.5...2...9..7.62.6..587.8492...........26.49.5..62.5....941.6.142...7
* PAIR A3: 1,3 BLK 1
A2: 1,3,7                                # reduction candidate for 1,3
A2: 1,3                                  # 26 pairs
B2: 1,3,7,8                              # reduction candidate for 1,3
B2: 1,3 => CTR
* 965872.4...4.5..82...9..7562.6..587.8492...35.5....26.49.5..62.5726.941.6.142.597
* RESTART
* PAIR A3: 1,3 BLK 1
A2: 1,3,7                                # reduction candidate for 1,3
A2: 7 => CTR
* 96.8.2.4.78465...21..9..7862.6..587.8492.6...3..1..26.49.5.762.5....941.6.142...7
* PAIR A3: 1,3 ROW 3
E3: 1,3,4                                # reduction candidate for 1,3
E3: 1,3 => CTR
* 96.8.2.4..74651.821.89347562.6..587.8492.6.357531.826.4975..62.5....941.681423..7
* RESTART
* PAIR RESTART
* PAIR D2: 6,7 BLK 2
F2: 6,7,1,3                              # reduction candidate for 6,7
F2: 6,7 => SOLVED
* 967812345384756192125943786216395874849267531753184269498571623572639418631428957
* DURATION: 0:00:06.020934  START: 21:58:34.610107  END: 21:58:40.631041 2019-04-30
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20060327-absurd-base-pr-001.dot
* REASONING
* DIS # B2: 1,3 => CTR => B2: 7,8
* DIS B2: 7,8 # A2: 7 => CTR => A2: 1,3
* DIS B2: 7,8 + A2: 1,3 # E3: 1,3 => CTR => E3: 4
* PRF B2: 7,8 + A2: 1,3 + E3: 4 # F2: 6,7 => SOL
* STA B2: 7,8 + A2: 1,3 + E3: 4 + F2: 6,7
* CNT   4 HDP CHAINS /   6 HYP OPENED

Header Info

http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Mar&YEAR=2006, 20060327, absurd

Solution

position: 967812345384756192125943786216395874849267531753184269498571623572639418631428957 solved
Solution

See section Pair Reduction for the HDP chains leading to this result.

Appendix: Full HDP Chains

A1. Pair Reduction Analysis

Full list of HDP chains traversed:

* INC # A2: 1,3 => UNS
* DIS # B2: 1,3 => CTR => B2: 7,8
* INC # B2: 7,8 => UNS
* DIS # E3: 1,3 => CTR => E3: 4
* INC # E3: 4 => UNS
* INC # F3: 1,3 => UNS
* DIS # A6: 1,3 => CTR => A6: 7
* INC # A6: 7 => UNS
* PRF # F2: 6,7 => SOL
* DIS # F2: 1,3 => CTR => F2: 6,7
* INC # G1: 1,5 => UNS
* INC # G1: 3 => UNS
* DIS # B3: 5,8 => CTR => B3: 2
* INC # B3: 2 => UNS
* INC # C3: 5,8 => UNS
* DIS # A6: 1,3 => CTR => A6: 7
* INC # A6: 7 => UNS
* DIS # B6: 1,3 => CTR => B6: 5,7
* INC # B6: 5,7 => UNS
* DIS # B2: 1,3 => CTR => B2: 7,8
* INC # B2: 7,8 => UNS
* DIS # E6: 4,9 => CTR => E6: 8
* INC # E6: 8 => UNS
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # E8: 3,8 => SOL
* PRF # F2: 6,7 => SOL
* DIS # F2: 1,3 => CTR => F2: 6,7
* DIS # A6: 1,3 => CTR => A6: 7
* INC # A6: 7 => UNS
* DIS # B6: 1,3 => CTR => B6: 5,7
* INC # B6: 5,7 => UNS
* INC # E6: 4,8 => UNS
* DIS # E6: 9 => CTR => E6: 4,8
* INC # G5: 3,5 => UNS
* INC # G5: 1 => UNS
* INC # G5: 1,5 => UNS
* INC # G5: 3 => UNS
* DIS # E6: 4,9 => CTR => E6: 8
* INC # E6: 8 => UNS
* PRF # C7: 3,8 => SOL
* DIS # C7: 7 => CTR => C7: 3,8
* DIS # B8: 3,8 => CTR => B8: 2,7
* INC # B8: 2,7 => UNS
* DIS # C8: 3,8 => CTR => C8: 2,7
* INC # C8: 2,7 => UNS
* INC # B2: 3,8 => UNS
* DIS # B2: 1,7 => CTR => B2: 3,8
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # E8: 3,8 => SOL
* DIS # E7: 3,8 => CTR => E7: 1,7
* INC # E7: 1,7 => UNS
* DIS # F7: 3,8 => CTR => F7: 1,7
* INC # F7: 1,7 => UNS
* PRF # E8: 3,8 => SOL
* DIS # E8: 6,7 => CTR => E8: 3,8
* PRF # C7: 3,8 => SOL
* DIS # C7: 7 => CTR => C7: 3,8
* DIS # E7: 3,8 => CTR => E7: 1,7
* INC # E7: 1,7 => UNS
* DIS # F7: 3,8 => CTR => F7: 1,7
* INC # F7: 1,7 => UNS
* DIS # B8: 3,8 => CTR => B8: 2,7
* INC # B8: 2,7 => UNS
* DIS # C8: 3,8 => CTR => C8: 2,7
* INC # C8: 2,7 => UNS
* PRF # E8: 3,8 => SOL
* DIS # E8: 6,7 => CTR => E8: 3,8
* CNT  67 HDP CHAINS /  67 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A2: 1,3 => UNS
* DIS # B2: 1,3 => CTR => B2: 7,8
* INC B2: 7,8 # A2: 1,3 => UNS
* DIS B2: 7,8 # A2: 7 => CTR => A2: 1,3
* DIS B2: 7,8 + A2: 1,3 # E3: 1,3 => CTR => E3: 4
* PRF B2: 7,8 + A2: 1,3 + E3: 4 # F2: 6,7 => SOL
* STA B2: 7,8 + A2: 1,3 + E3: 4 + F2: 6,7
* CNT   6 HDP CHAINS /   6 HYP OPENED