Analysis of zz-www.sudokuoftheday.co.uk-20190204-absurd-base.sdk

Contents

Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Feb&YEAR=2019

level: medium

Sudoku from http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Feb&YEAR=2019

position: 4...7.1.....92.5...72.......3..4.....1....9.89.63........7...1436.48............9 initial

Autosolve

position: 49..7.1...8.92.5...72....9..3..49....14..79389.63.8......79..14369481....4...2..9 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F1: 6 => CTR => F1: 3,5
* PRF # F3: 5,6 => SOL
* DIS # F3: 3,4 => CTR => F3: 5,6
* PRF # D3: 6,8 => SOL
* DIS # D3: 1 => CTR => D3: 6,8
* DIS # H1: 2 => CTR => H1: 6,8
* DIS # I1: 3,6 => CTR => I1: 2
* PRF # I2: 3,6 => SOL
* DIS # E3: 3,6 => CTR => E3: 1
* PRF # E3: 1 => SOL
* DIS # F3: 3,6 => CTR => F3: 4,5
* DIS # D5: 6 => CTR => D5: 2,5
* PRF # A7: 2,5 => SOL
* DIS # A7: 8 => CTR => A7: 2,5
* DIS # H6: 2,5 => CTR => H6: 4,7
* DIS # I6: 2,5 => CTR => I6: 1,7
* DIS # D5: 5,6 => CTR => D5: 2
* PRF # D5: 2 => SOL
* DIS # E9: 5,6 => CTR => E9: 3
* PRF # D4: 1,5 => SOL
* DIS # D4: 2 => CTR => D4: 1,5
* PRF # I6: 1,5 => SOL
* DIS # I6: 2,7 => CTR => I6: 1,5
* PRF # H4: 2,6 => SOL
* DIS # I4: 2,6 => CTR => I4: 1,5
* PRF # A7: 2,5 => SOL
* DIS # A7: 8 => CTR => A7: 2,5
* DIS # A7: 5,8 => CTR => A7: 2
* PRF # A7: 2 => SOL
* DIS # E9: 5 => CTR => E9: 3,6
* PRF # F1: 3,6 => SOL
* DIS # F1: 5 => CTR => F1: 3,6
* DIS # F2: 3,6 => CTR => F2: 4
* PRF # F2: 4 => SOL
* DIS # F3: 3,6 => CTR => F3: 4,5
* DIS # E9: 5,6 => CTR => E9: 3
* DIS # D5: 5,6 => CTR => D5: 2
* PRF # D5: 2 => SOL
* DIS # G9: 3,6 => CTR => G9: 8
* PRF # G9: 8 => SOL
* PRF # I8: 2,7 => SOL
* PRF # G6: 2,7 => SOL
* DIS # G6: 4 => CTR => G6: 2,7
* DIS # G9: 3 => CTR => G9: 6,8
* DIS # H1: 2 => CTR => H1: 6,8
* CNT  45 HDP CHAINS /  63 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 # F1: 6 => CTR => F1: 3,5
* PRF F1: 3,5 # F3: 5,6 => SOL
* STA F1: 3,5 + F3: 5,6
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

4...7.1.....92.5...72.......3..4.....1....9.89.63........7...1436.48............9 initial
49..7.1...8.92.5...72....9..3..49....14..79389.63.8......79..14369481....4...2..9 autosolve
495673182183924576672815493837149625514267938926358741258796314369481257741532869 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (22)
C1: 3,5
A2: 1,6
C2: 1,3
A3: 5,6
D1: 6,8
I3: 3,6
A4: 7,8
C4: 7,8
A5: 2,5
B6: 2,5
E5: 5,6
E6: 1,5
G4: 2,6
B7: 2,5
C7: 5,8
A9: 1,7
C9: 1,7
F7: 3,6
D9: 5,6
G7: 3,6
G8: 2,7
H9: 6,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,C2: 1.. / A2 = 1  =>  0 pairs (*) / C2 = 1  =>  0 pairs (X)
D3,E3: 1.. / D3 = 1  =>  0 pairs (X) / E3 = 1  =>  0 pairs (_)
D4,E6: 1.. / D4 = 1  =>  0 pairs (*) / E6 = 1  =>  0 pairs (X)
I4,I6: 1.. / I4 = 1  =>  0 pairs (X) / I6 = 1  =>  0 pairs (_)
A9,C9: 1.. / A9 = 1  =>  0 pairs (X) / C9 = 1  =>  0 pairs (_)
D4,I4: 1.. / D4 = 1  =>  0 pairs (*) / I4 = 1  =>  0 pairs (X)
E6,I6: 1.. / E6 = 1  =>  0 pairs (X) / I6 = 1  =>  0 pairs (_)
A2,A9: 1.. / A2 = 1  =>  0 pairs (*) / A9 = 1  =>  0 pairs (X)
C2,C9: 1.. / C2 = 1  =>  0 pairs (X) / C9 = 1  =>  0 pairs (_)
D3,D4: 1.. / D3 = 1  =>  0 pairs (X) / D4 = 1  =>  0 pairs (_)
E3,E6: 1.. / E3 = 1  =>  0 pairs (*) / E6 = 1  =>  0 pairs (X)
H1,I1: 2.. / H1 = 2  =>  0 pairs (X) / I1 = 2  => 27 pairs (_)
A5,B6: 2.. / A5 = 2  =>  0 pairs (X) / B6 = 2  =>  0 pairs (_)
D4,D5: 2.. / D4 = 2  =>  0 pairs (X) / D5 = 2  =>  0 pairs (_)
A7,B7: 2.. / A7 = 2  =>  0 pairs (*) / B7 = 2  =>  0 pairs (X)
A5,D5: 2.. / A5 = 2  =>  0 pairs (X) / D5 = 2  =>  0 pairs (_)
A5,A7: 2.. / A5 = 2  =>  0 pairs (X) / A7 = 2  =>  0 pairs (_)
B6,B7: 2.. / B6 = 2  =>  0 pairs (*) / B7 = 2  =>  0 pairs (X)
C1,C2: 3.. / C1 = 3  =>  0 pairs (X) / C2 = 3  =>  0 pairs (_)
F7,E9: 3.. / F7 = 3  =>  0 pairs (X) / E9 = 3  => 26 pairs (_)
G7,G9: 3.. / G7 = 3  => 26 pairs (_) / G9 = 3  =>  0 pairs (X)
F7,G7: 3.. / F7 = 3  =>  0 pairs (X) / G7 = 3  => 26 pairs (_)
E9,G9: 3.. / E9 = 3  => 26 pairs (_) / G9 = 3  =>  0 pairs (X)
E3,E9: 3.. / E3 = 3  =>  0 pairs (X) / E9 = 3  => 26 pairs (_)
F2,F3: 4.. / F2 = 4  =>  0 pairs (*) / F3 = 4  =>  0 pairs (X)
H2,G3: 4.. / H2 = 4  =>  0 pairs (X) / G3 = 4  =>  0 pairs (_)
G6,H6: 4.. / G6 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
F2,H2: 4.. / F2 = 4  =>  0 pairs (*) / H2 = 4  =>  0 pairs (X)
F3,G3: 4.. / F3 = 4  =>  0 pairs (X) / G3 = 4  =>  0 pairs (_)
G3,G6: 4.. / G3 = 4  =>  0 pairs (*) / G6 = 4  =>  0 pairs (X)
H2,H6: 4.. / H2 = 4  =>  0 pairs (X) / H6 = 4  =>  0 pairs (_)
C1,A3: 5.. / C1 = 5  =>  0 pairs (*) / A3 = 5  =>  0 pairs (X)
F1,F3: 5.. / F1 = 5  =>  0 pairs (X) / F3 = 5  =>  0 pairs (_)
A5,B6: 5.. / A5 = 5  =>  0 pairs (*) / B6 = 5  =>  0 pairs (X)
D9,E9: 5.. / D9 = 5  => 24 pairs (_) / E9 = 5  =>  0 pairs (X)
H8,I8: 5.. / H8 = 5  =>  0 pairs (*) / I8 = 5  =>  0 pairs (X)
C1,F1: 5.. / C1 = 5  =>  0 pairs (*) / F1 = 5  =>  0 pairs (X)
A3,F3: 5.. / A3 = 5  =>  0 pairs (X) / F3 = 5  =>  0 pairs (_)
B6,B7: 5.. / B6 = 5  =>  0 pairs (X) / B7 = 5  =>  0 pairs (_)
C1,C7: 5.. / C1 = 5  =>  0 pairs (*) / C7 = 5  =>  0 pairs (X)
A2,A3: 6.. / A2 = 6  =>  0 pairs (X) / A3 = 6  =>  0 pairs (_)
D5,E5: 6.. / D5 = 6  =>  0 pairs (X) / E5 = 6  => 24 pairs (_)
F7,G7: 6.. / F7 = 6  => 26 pairs (_) / G7 = 6  =>  0 pairs (X)
H2,I2: 7.. / H2 = 7  =>  0 pairs (*) / I2 = 7  =>  0 pairs (X)
A4,C4: 7.. / A4 = 7  =>  0 pairs (X) / C4 = 7  =>  0 pairs (_)
A9,C9: 7.. / A9 = 7  =>  0 pairs (*) / C9 = 7  =>  0 pairs (X)
A4,A9: 7.. / A4 = 7  =>  0 pairs (X) / A9 = 7  =>  0 pairs (_)
C4,C9: 7.. / C4 = 7  =>  0 pairs (*) / C9 = 7  =>  0 pairs (X)
G6,G8: 7.. / G6 = 7  =>  0 pairs (*) / G8 = 7  =>  0 pairs (X)
D1,D3: 8.. / D1 = 8  =>  0 pairs (X) / D3 = 8  =>  0 pairs (_)
H1,G3: 8.. / H1 = 8  =>  0 pairs (*) / G3 = 8  =>  0 pairs (X)
A4,C4: 8.. / A4 = 8  =>  0 pairs (*) / C4 = 8  =>  0 pairs (X)
A7,C7: 8.. / A7 = 8  =>  0 pairs (X) / C7 = 8  =>  0 pairs (_)
G9,H9: 8.. / G9 = 8  =>  0 pairs (*) / H9 = 8  =>  0 pairs (X)
D1,H1: 8.. / D1 = 8  =>  0 pairs (X) / H1 = 8  =>  0 pairs (_)
D3,G3: 8.. / D3 = 8  =>  0 pairs (*) / G3 = 8  =>  0 pairs (X)
A4,A7: 8.. / A4 = 8  =>  0 pairs (*) / A7 = 8  =>  0 pairs (X)
C4,C7: 8.. / C4 = 8  =>  0 pairs (X) / C7 = 8  =>  0 pairs (_)
G3,G9: 8.. / G3 = 8  =>  0 pairs (X) / G9 = 8  =>  0 pairs (_)
H1,H9: 8.. / H1 = 8  =>  0 pairs (*) / H9 = 8  =>  0 pairs (X)
* DURATION: 0:01:26.871564  START: 03:28:02.818355  END: 03:29:29.689919 2019-05-01
* CP COUNT: (60)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,A4,A5,A9,B6,B7,C1,C2,C4,C7,C9,D1,D9,E5,E6,F7,G4,G7,G8,H9,I3)
* 49..7.1...8.92.5...72....9..3..49....14..79389.63.8......79..14369481....4...2..9
* PAIR C1: 3,5 ROW 1
F1: 3,5,6                                # reduction candidate for 3,5
F1: 6 => CTR
* 495.761.3.839245..672....9..3..49....14..79389.63.8......79..14369481....4...2..9
F1: 3,5                                  # 24 pairs
* PAIR A3: 5,6 ROW 3
F3: 5,6,3,4                              # reduction candidate for 5,6
F3: 5,6 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
F3: 3,4 => CTR
* 493.751..68192.5..5721..89.73824965.214..7938956318...82579..14369481....4...2..9
* PAIR D1: 6,8 BLK 2
D3: 6,8,1                                # reduction candidate for 6,8
D3: 6,8 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
D3: 1 => CTR
* 49587.12..8392654767213489..3..49261.1426793892631847525879..14369481752.4.652389
* PAIR D1: 6,8 ROW 1
H1: 6,8,2                                # reduction candidate for 6,8
H1: 2 => CTR
* 49587.12..8392654767213489..3..4926..142679389263.847.25879..14369481752.4...2.89
H1: 6,8                                  # 27 pairs
* PAIR I3: 3,6 BLK 3
I1: 3,6,2                                # reduction candidate for 3,6
I1: 3,6 => CTR
* 49587.12..8392654767213489..3..4926..142679389263.847.25879..14369481752.4...2.89
I1: 2                                    # 27 pairs
I2: 3,6,7                                # reduction candidate for 3,6
I2: 3,6 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
I2: 7                                    # 26 pairs
* PAIR I3: 3,6 ROW 3
E3: 3,6,1                                # reduction candidate for 3,6
E3: 3,6 => CTR
* 49587.12..8392654767213489..3..49261.1426793892631847525879..14369481752.4.652389
E3: 1 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
F3: 3,6,4,5                              # reduction candidate for 3,6
F3: 3,6 => CTR
* 49..751...8.9245..572...49..3..49...214..7938956318.4.82579..14369481....4...2869
F3: 4,5                                  # 23 pairs
* PAIR A5: 2,5 ROW 5
D5: 2,5,6                                # reduction candidate for 2,5
D5: 6 => CTR
* 49..7.1...8.92.5...72....9..3.249651214657938956318....2.796314369481..5.4.532869
D5: 2,5                                  # 24 pairs
* PAIR A5: 2,5 COL A
A7: 2,5,8                                # reduction candidate for 2,5
A7: 2,5 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
A7: 8 => CTR
* 493.751...8192.5..5721..89.73824965.214..7938956318...82579..14369481....4...2..9
* PAIR B6: 2,5 ROW 6
H6: 2,5,4,7                              # reduction candidate for 2,5
H6: 2,5 => CTR
* 49..7.1...8.92.547.72..4.9..3..49....14..79389.63.8......79..14369481....4...2..9
H6: 4,7                                  # 23 pairs
I6: 2,5,1,7                              # reduction candidate for 2,5
I6: 2,5 => CTR
* 49587.12..8392654767213489..3..49261.1426793892631847525879..14369481752.4.652389
I6: 1,7                                  # 23 pairs
* PAIR E5: 5,6 BLK 5
D5: 5,6,2                                # reduction candidate for 5,6
D5: 5,6 => CTR
* 49..7.1...8.92.5...72....9..3.249651214..7938956318....2.796314369481..5.4.532869
D5: 2 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
* PAIR E5: 5,6 COL E
E9: 5,6,3                                # reduction candidate for 5,6
E9: 5,6 => CTR
* 49.87612368.92.5...72.3..96.3..49....14..79389.6318......793614369481....4...2389
E9: 3                                    # 26 pairs
* PAIR E6: 1,5 BLK 5
D4: 1,5,2                                # reduction candidate for 1,5
D4: 1,5 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
D4: 2 => CTR
* 49..7.1...8.92.5...721..89..3.24965..14..79389.63.8......79..14369481....4...2..9
* PAIR E6: 1,5 ROW 6
I6: 1,5,2,7                              # reduction candidate for 1,5
I6: 1,5 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
I6: 2,7 => CTR
* 49.87.162.8.92.547.721..89..3..49..1.14..79389.63184.....79..14369481725.4...2.89
* PAIR G4: 2,6 BLK 6
H4: 2,6,5                                # reduction candidate for 2,6
H4: 2,6 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
H4: 5                                    # 24 pairs
I4: 2,6,1,5                              # reduction candidate for 2,6
I4: 2,6 => CTR
* 495.7.1...8392.5.7672815493837149.5.514267938926358741258796314369481275.4.532..9
I4: 1,5                                  # 26 pairs
* PAIR B7: 2,5 BLK 7
A7: 2,5,8                                # reduction candidate for 2,5
A7: 2,5 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
A7: 8 => CTR
* 493.751...8192.5..5721..89.73824965.214..7938956318...82579..14369481....4...2..9
* PAIR C7: 5,8 BLK 7
A7: 5,8,2                                # reduction candidate for 5,8
A7: 5,8 => CTR
* 49..7.1...8.92.5...721..89..3.24965.214..7938956318....2.79..14369481....4...2..9
A7: 2 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
* PAIR F7: 3,6 BLK 8
E9: 3,6,5                                # reduction candidate for 3,6
E9: 5 => CTR
* 49.87612368.92.5...72.3..96.3..49....14.679389.6318......793614369481....4.652389
E9: 3,6                                  # 24 pairs
* PAIR F7: 3,6 COL F
F1: 3,6,5                                # reduction candidate for 3,6
F1: 3,6 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
F1: 5 => CTR
* 493.751..68192.5..5721..89.73824965.214..7938956318...82579..14369481....4...2..9
F2: 3,6,4                                # reduction candidate for 3,6
F2: 3,6 => CTR
* 49..751...8.92.547572..4.9..3..492..214..79389.63.847....79..143694817...4...2..9
F2: 4 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
F3: 3,6,4,5                              # reduction candidate for 3,6
F3: 3,6 => CTR
* 49..751...8.9245..572...49..3..49...214..7938956318.4.82579..14369481....4...2869
F3: 4,5                                  # 23 pairs
* PAIR D9: 5,6 BLK 8
E9: 5,6,3                                # reduction candidate for 5,6
E9: 5,6 => CTR
* 49.87612368.92.5...72.3..96.3..49....14..79389.6318......793614369481....4...2389
E9: 3                                    # 26 pairs
* PAIR D9: 5,6 COL D
D5: 5,6,2                                # reduction candidate for 5,6
D5: 5,6 => CTR
* 49..7.1...8.92.5...72....9..3.249651214..7938956318....2.796314369481..5.4.532869
D5: 2 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
* PAIR G7: 3,6 BLK 9
G9: 3,6,8                                # reduction candidate for 3,6
G9: 3,6 => CTR
* 49587.1...8392654767213489..3..492...142679389263.847.25879..143694817...4...2.89
G9: 8 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
* PAIR G8: 2,7 BLK 9
H8: 2,7,5                                # reduction candidate for 2,7
H8: 2,7                                  # 23 pairs
I8: 2,7,5                                # reduction candidate for 2,7
I8: 2,7 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
I8: 5                                    # 23 pairs
* PAIR G8: 2,7 COL G
G6: 2,7,4                                # reduction candidate for 2,7
G6: 2,7 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
G6: 4 => CTR
* 495.7.1...83926547672..4893837.492..5142679389263.847.258793.143694817...4...2..9
* PAIR H9: 6,8 BLK 9
G9: 6,8,3                                # reduction candidate for 6,8
G9: 3 => CTR
* 49.87.1...8.92.547.72.34896.3..4926..14267938926318475258793.143694817...4...2389
G9: 6,8                                  # 26 pairs
* PAIR H9: 6,8 COL H
H1: 6,8,2                                # reduction candidate for 6,8
H1: 2 => CTR
* 49587.12..8392654767213489..3..4926..142679389263.847.25879..14369481752.4...2.89
H1: 6,8                                  # 27 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20190204-absurd-base-pr-000.dot
* REASONING
* DIS # F1: 6 => CTR => F1: 3,5
* PRF # F3: 5,6 => SOL
* DIS # F3: 3,4 => CTR => F3: 5,6
* PRF # D3: 6,8 => SOL
* DIS # D3: 1 => CTR => D3: 6,8
* DIS # H1: 2 => CTR => H1: 6,8
* DIS # I1: 3,6 => CTR => I1: 2
* PRF # I2: 3,6 => SOL
* DIS # E3: 3,6 => CTR => E3: 1
* PRF # E3: 1 => SOL
* DIS # F3: 3,6 => CTR => F3: 4,5
* DIS # D5: 6 => CTR => D5: 2,5
* PRF # A7: 2,5 => SOL
* DIS # A7: 8 => CTR => A7: 2,5
* DIS # H6: 2,5 => CTR => H6: 4,7
* DIS # I6: 2,5 => CTR => I6: 1,7
* DIS # D5: 5,6 => CTR => D5: 2
* PRF # D5: 2 => SOL
* DIS # E9: 5,6 => CTR => E9: 3
* PRF # D4: 1,5 => SOL
* DIS # D4: 2 => CTR => D4: 1,5
* PRF # I6: 1,5 => SOL
* DIS # I6: 2,7 => CTR => I6: 1,5
* PRF # H4: 2,6 => SOL
* DIS # I4: 2,6 => CTR => I4: 1,5
* PRF # A7: 2,5 => SOL
* DIS # A7: 8 => CTR => A7: 2,5
* DIS # A7: 5,8 => CTR => A7: 2
* PRF # A7: 2 => SOL
* DIS # E9: 5 => CTR => E9: 3,6
* PRF # F1: 3,6 => SOL
* DIS # F1: 5 => CTR => F1: 3,6
* DIS # F2: 3,6 => CTR => F2: 4
* PRF # F2: 4 => SOL
* DIS # F3: 3,6 => CTR => F3: 4,5
* DIS # E9: 5,6 => CTR => E9: 3
* DIS # D5: 5,6 => CTR => D5: 2
* PRF # D5: 2 => SOL
* DIS # G9: 3,6 => CTR => G9: 8
* PRF # G9: 8 => SOL
* PRF # I8: 2,7 => SOL
* PRF # G6: 2,7 => SOL
* DIS # G6: 4 => CTR => G6: 2,7
* DIS # G9: 3 => CTR => G9: 6,8
* DIS # H1: 2 => CTR => H1: 6,8
* CNT  45 HDP CHAINS /  63 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A3,A4,A5,A9,B6,B7,C1,C2,C4,C7,C9,D1,D9,E5,E6,F7,G4,G7,G8,H9,I3)
* 49..7.1...8.92.5...72....9..3..49....14..79389.63.8......79..14369481....4...2..9
* PAIR C1: 3,5 ROW 1
F1: 3,5,6                                # reduction candidate for 3,5
F1: 6 => CTR
* 495.761.3.839245..672....9..3..49....14..79389.63.8......79..14369481....4...2..9
* PAIR RESTART
* PAIR A3: 5,6 ROW 3
F3: 5,6,3,4                              # reduction candidate for 5,6
F3: 5,6 => SOLVED
* 495673182183924576672815493837149625514267938926358741258796314369481257741532869
* DURATION: 0:00:03.452764  START: 03:30:24.585128  END: 03:30:28.037892 2019-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-www.sudokuoftheday.co.uk-20190204-absurd-base-pr-001.dot
* REASONING
* DIS # F1: 6 => CTR => F1: 3,5
* PRF F1: 3,5 # F3: 5,6 => SOL
* STA F1: 3,5 + F3: 5,6
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

http://www.sudokuoftheday.co.uk/cgi-bin/sudoku1280.cgi?ACTION=archive2&USER=&MONTH=Feb&YEAR=2019, 20190204, absurd

Solution

position: 495673182183924576672815493837149625514267938926358741258796314369481257741532869 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 # F1: 3,5 => UNS
* DIS # F1: 6 => CTR => F1: 3,5
* PRF # F3: 5,6 => SOL
* DIS # F3: 3,4 => CTR => F3: 5,6
* PRF # D3: 6,8 => SOL
* DIS # D3: 1 => CTR => D3: 6,8
* INC # H1: 6,8 => UNS
* DIS # H1: 2 => CTR => H1: 6,8
* DIS # I1: 3,6 => CTR => I1: 2
* INC # I1: 2 => UNS
* PRF # I2: 3,6 => SOL
* INC # I2: 7 => UNS
* DIS # E3: 3,6 => CTR => E3: 1
* PRF # E3: 1 => SOL
* DIS # F3: 3,6 => CTR => F3: 4,5
* INC # F3: 4,5 => UNS
* INC # D5: 2,5 => UNS
* DIS # D5: 6 => CTR => D5: 2,5
* PRF # A7: 2,5 => SOL
* DIS # A7: 8 => CTR => A7: 2,5
* DIS # H6: 2,5 => CTR => H6: 4,7
* INC # H6: 4,7 => UNS
* DIS # I6: 2,5 => CTR => I6: 1,7
* INC # I6: 1,7 => UNS
* DIS # D5: 5,6 => CTR => D5: 2
* PRF # D5: 2 => SOL
* DIS # E9: 5,6 => CTR => E9: 3
* INC # E9: 3 => UNS
* PRF # D4: 1,5 => SOL
* DIS # D4: 2 => CTR => D4: 1,5
* PRF # I6: 1,5 => SOL
* DIS # I6: 2,7 => CTR => I6: 1,5
* PRF # H4: 2,6 => SOL
* INC # H4: 5 => UNS
* DIS # I4: 2,6 => CTR => I4: 1,5
* INC # I4: 1,5 => UNS
* PRF # A7: 2,5 => SOL
* DIS # A7: 8 => CTR => A7: 2,5
* DIS # A7: 5,8 => CTR => A7: 2
* PRF # A7: 2 => SOL
* INC # E9: 3,6 => UNS
* DIS # E9: 5 => CTR => E9: 3,6
* PRF # F1: 3,6 => SOL
* DIS # F1: 5 => CTR => F1: 3,6
* DIS # F2: 3,6 => CTR => F2: 4
* PRF # F2: 4 => SOL
* DIS # F3: 3,6 => CTR => F3: 4,5
* INC # F3: 4,5 => UNS
* DIS # E9: 5,6 => CTR => E9: 3
* INC # E9: 3 => UNS
* DIS # D5: 5,6 => CTR => D5: 2
* PRF # D5: 2 => SOL
* DIS # G9: 3,6 => CTR => G9: 8
* PRF # G9: 8 => SOL
* INC # H8: 2,7 => UNS
* PRF # I8: 2,7 => SOL
* INC # I8: 5 => UNS
* PRF # G6: 2,7 => SOL
* DIS # G6: 4 => CTR => G6: 2,7
* INC # G9: 6,8 => UNS
* DIS # G9: 3 => CTR => G9: 6,8
* INC # H1: 6,8 => UNS
* DIS # H1: 2 => CTR => H1: 6,8
* CNT  63 HDP CHAINS /  63 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # F1: 3,5 => UNS
* DIS # F1: 6 => CTR => F1: 3,5
* PRF F1: 3,5 # F3: 5,6 => SOL
* STA F1: 3,5 + F3: 5,6
* CNT   3 HDP CHAINS /   3 HYP OPENED