L'infaisable n°4

Bonjour à tous,

En voilà une qui méritait bien son qualificatif d'infaisable. Quelle galère !

C'est une grille dont on aurait dit autrefois : "abi, c'est pour toi !"


_ | a______ b______ c_____ | d______ e_____ f_______ | g_____ h_____ i____ |
1 | 1f3á78ç 7a8A___ ______ | 1F2h37_ ______ ________ | 278t__ 23â7__ _____ |
2 | _______ 679____ 13j679 | _______ 1359__ 13579___ | 5m67__ ______ 1y67_ |
3 | _______ 678t9__ 13679_ | 12357__ 1359__ 12z3579_ | 25678T 23Â5ä7 1Y267 |

4 | 3578u9w _______ 34c79W | 357____ 34C58V 3578____ | 25ä6o7 2à57__ 26O7_ |
5 | 35678__ 5678ç__ 367___ | 1g356æ7 ______ 1G35678u | ______ 5b7B__ _____ |
6 | 567____ 2i4l567 2I467_ | _______ 4c5C__ 56p7r___ | ______ ______ _____ |

7 | 1567___ 25ã67__ 1267__ | _______ 1358v_ 12356q8V | 23k7__ ______ 2d7D_ |
8 | 15n79__ _______ 124l79 | 125____ 159é__ 1259____ | 24L7s_ ______ _____ |
9 | 6e9E___ 24L69è_ ______ | 236Æ___ ______ 2369x___ | 23K4l_ ______ _____ |

On commence par aller aussi loin que possible avec le marquage simple :

5d5/5e6-4c4/9c4-9a4/9a9-6a9/6d9-6d5/5d5 =>INTERDIT 5d5=Faux
8e4/4e4-4c4/9c4-9a4/9a9-6a9/6abc7-6f7/8f7-8e7/8e4 =>INTERDIT 8e4=Faux (e7=8, 8f4=U)
5f5/5e6-4e6/4e4-4c4/9c4-9a4/9a9-6a9/6d9-6d5/1d5-1f5/5f5 =>INTERDIT 5f5=Faux

1a8/1a1-1d1/1e23-1e8/1a8 =>INTERDIT 1a8=Faux
3f5/1f5-1d5/6d5-6d9/3d9-3f79/3f5 =>INTERDIT 3f5=Faux
5f4/5e6-4e6/4e4-4c4/9c4-9a4/8a4-8f4/5f4 =>INTERDIT 5f4=Faux
3f4/8f4-8f5/1f5-1d5/6d5-6d9/3d9-3f79/3f4 =>INTERDIT 3f4=Faux

3c4/3ac5-3d5/6d5-6d9/6a9-9a9/9a4-9c4/3c4 =>INTERDIT 3c4=Faux


_ | a_______ b______ c______ | d______ e____ f________ | g_____ h_____ i____ |
1 | 1f3á78ç_ 7a8A___ _______ | 1F2h37_ _____ _________ | 278t__ 23â7__ _____ |
2 | ________ 679____ 13j679_ | _______ 1359_ 13579____ | 5m67__ ______ 1y67_ |
3 | ________ 678t9__ 13679__ | 12357__ 1359_ 12z3579__ | 25678T 23Â5ä7 1Y267 |

4 | 3ë578u9w _______ 4c79W__ | 357____ 3õ4C5 7u8U_____ | 25ä6o7 2à57__ 26O7_ |
5 | 35678___ 5678ç__ 3á67___ | 1g3ë6æ7 _____ 1G678u___ | ______ 5b7B__ _____ |
6 | 567_____ 2i4l567 2I467__ | _______ 4c5C_ 56p7r____ | ______ ______ _____ |

7 | 1F567___ 25ã67__ 1267___ | _______ _____ 1Ê23K5n6q | 23k7__ ______ 2d7D_ |
8 | 5n79____ _______ 1Ê24l79 | 125____ 1Ï59é 1259_____ | 24L7s_ ______ _____ |
9 | 6e9E____ 24L69è_ _______ | 23ö6Æ__ _____ 2369x____ | 23K4l_ ______ _____ |

A partir de là, il faut sortir le char d'assaut : pseudo-cases et dérivés ternaires, pour trouver 10 éliminations qui vont débloquer la grille.

DERIVE TERNAIRE (2d9-3d9-6d9)+2d9/7a4+3d9/7a4=>!6d9/7a4
2d9/2df8-2cg8/7cg8(PC cg8)-7a8/7a4
3f23/3e23-3e4/4e4-4c4/9c4-9a4/7a4

DERIVE TERNAIRE (6d5-6f5-6f6)+6f5/7a4+6f6/7a4=>!6d5/7a4
6f5/1f5-1d5/1d1-1a1/7a145(PC a145)-7a678/7a4
6f6/7f6-7abc6/7a4

7a4/!6d9(DT)-!6d5/7a4(DT) =>INTERDIT 7a4=Faux
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DERIVE TERNAIRE (5a5-5b5-5h5)+5a5/7c4+5h5/7c4=>!5b5/7c4
5a5/5a68-5a457/9a4(PC a1457)-9c4/7c4
7ghi4/7c4

DERIVE TERNAIRE (5a7-5b7-5a8)+5a7/7c4+5a8/7c4=>!5b7/7c4
5a7/5a68-5a457/9a4(PC a1457)-9c4/7c4
5f7/6f7-6abc7/6a9-9a9/9a4-9c4/7c4

7c4/!5b5(DT)-5b5/5b7-!5b7/7c4(DT) =>INTERDIT 7c4=Faux
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DERIVE TERNAIRE (2d9-3d9-6d9)+3d9/5e4+6d9/5e4=>!2d9/5e4
3d9/3f79-3f23/3e23-3e4/5e4
6d9/6a9-9a9/9a4-9c4/4c4-4e4/5e4

DERIVE TERNAIRE (2g9-3g9-4g9)+3f7/5e4+4c8/5e4=>!2g9/5e4
3f7/6f7-6abc7/6a9-9a9/9a4-9c4/4c4-4e4/5e4
4b6/4e6-4e4/5e4

5e4/!2d9(DT)-2d9/2g9-!2g9/5e4(DT) =>INTERDIT 5e4=Faux
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DERIVE TERNAIRE (3c5-6c5-7c5)+6c5/6a5+7c5/6a5=>!3c5/6a5
6c5/6a5
7c5/7abc6-7f6/6f6-6abc6/6a5

DERIVE TERNAIRE (8a4-8a5-8b5)+8a4/6a5+8a5/6a5=>!8b5/6a5
8f5/1f5-1d5/1d1-1a1/6a5(PC a145)
8a5/6a5

6a5/!3c5(DT)-3a1/8a1-!8b5/6a5(DT) =>INTERDIT 6a5=Faux
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DERIVE TERNAIRE (5f6-6f6-7f6)+5f6/5a6+6f6/5a6=>!7f6/5a6
5f6/5a6
6f6/6d5-6d9/6a9-9a9/9a4-9c4/4c4-5e6/5a6

DERIVE TERNAIRE (5a6-6a6-7a6)+6a6/7bc6+7a6/7bc6=>!5a6/7bc6
6a6/6a9-9a9/9a4-9c4/4c4-5e6/5af6-5be6/7bc6(PC bce6)
7a6/7bc6

7bc6/7f6-!7f6/5a6(DT)-!5a6/7bc6(DT) =>INTERDIT 7bc6=Faux
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DERIVE TERNAIRE (5a7-5b7-5a8)+5a7/4e6+5a8/4e6=>!5b7/4e6
5a7/5a68-5a457/9a4(PC a1a4a5a7)-9c4/4c4
5f7/6f7-6abc7/6a9-9a9/9a4-9c4/4c4

5b6/5b7-!5b7/4e6(DT)-5e6/5b6 =>INTERDIT 5b6=Faux

6b6/6b2357-6b69/2b69(PC b69)-2b7/5b7-!5b7/4e6(DT)-4bc6/6bc6(PC bc6)-6af6/6b6 =>INTERDIT 6b6=Faux
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DERIVE TERNAIRE (3f7-3d9-3f9)+3f7/9f9+3f9/9f9=>!3d9/9f9
3f7/6f7-6abc7/6a9-9a9/9f9
3f9/9f9

DERIVE TERNAIRE (3d4-3e4-3d5)+3e4/9a8+3d5/9a8=>!3d4/9a8
3e4/4e4-4c4/9c4-9a4/9a8
3d5/6d5-6d9/6a9-9a9/9a8

9a8/9ab9-9f9/!3d9(DT)-3d9/3d134-3d59/3d4-!3d4/9a8(DT) =>INTERDIT 9a8=Faux
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DERIVE TERNAIRE (3c5-6c5-7c5)+6c5/6b9+7c5/6b9=>!3c5/6b9
6c5/6c23-6b23/6b9
7c5/7h5-5h5/5b5-5b67/6b679(PC b679)-6b235/6b9

DERIVE TERNAIRE (5a7-5b7-5a8)+5b7/6b9+5a8/6b9=>!5a7/6b9
5b7/2b7-2b69/6b69(PC b69)-6b2357/6b9
5f7/6f7-6abc7/6b9

6b9/!3c5(DT)-3a1/1a1-1a7/5a7-!5a7/6b9(DT) =>INTERDIT 6b9=Faux
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DERIVE TERNAIRE (5a7-5b7-5a8)+5a7/9a4+5a8/9a4=>!5b7/9a4
5a7/5a68-5a457/9a4(PC a1457)
5f7/6f7-6abc7/6a9-9a9/9a4

9b9/2b69(PC b69)-2b7/5b7-!5b7/9a4(DT)-9c4/9c23 =>INTERDIT è=Faux (-9b9, -9c23)
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_ | a______ b_____ c_______ | d______ e____ f________ | g_____ h_____ i____ |
1 | 1f3á78ç 7a8A__ ________ | 1F2h37_ _____ _________ | 278t__ 23â7__ _____ |
2 | _______ 679î__ 13j67___ | _______ 1359_ 13579____ | 5m67__ ______ 1y67_ |
3 | _______ 678t9Î 1367____ | 12357__ 1359_ 12z3579__ | 25678T 23Â5ä7 1Y267 |

4 | 3ë58u9c ______ 4c9C____ | 35ì7___ 3c4C_ 7u8U_____ | 25ä6o7 2à57__ 26O7_ |
5 | 3578___ 5Ã678ç 3á67____ | 1g3ë6æ7 _____ 1G678u___ | ______ 5b7B__ _____ |
6 | 5ì6ñ7R_ 2i4I__ 2I46c___ | _______ 4c5C_ 56p7r____ | ______ ______ _____ |

7 | 1F567__ 5ã67__ 1267____ | _______ _____ 1Ê23K5n6c | 23k7__ ______ 2d7D_ |
8 | 5n7N___ ______ 1Ê24I79c | 125____ 1Ï59é 1259_____ | 24i7s_ ______ _____ |
9 | 6c9C___ 2I4i__ ________ | 23ö6Æ__ _____ 2369c____ | 23K4I_ ______ _____ |

5a5/5h5-7h5/7bc5-7a6/7a8-5a8/5a5 =>INTERDIT 5a5=Faux
6b5/6ac6-6f6/7f6-7a6/7a8-5a8/5b7-5b5/6b5 =>INTERDIT 6b5=Faux
5b7-5b5/5h5-7h5/7bc5-7a6/6a6-6a79 =>INTERDIT 6b7=Faux

On a alors un peu de nettoyage (b157=578, a8.b7=57, g3=8, g24=56)

5f6/5f7-5b7/5a8-7a8/7a6-7f6/5f6 =>INTERDIT 5f6=Faux

Ce qui permet de finir :
5e2/5g2-5g4/5d4-5e6/5e2 =>INTERDIT 5e2=Faux
5f2/5def3-5h3/5h5-5b5/5b7-5f7/5f2 =>INTERDIT 5f2=Faux
5h4/2h4-2i4/2i7-7i7/7b7-5b7/5b5-5h5/5h4 =>INTERDIT 5h4=Faux

FIN...

Pas franchement coopérative, celle-ci !
J'avais jeté l'éponge dans le passé (https://sudokuvariante.forumactif.com/t1458-une-22-cases-a-decouvrir-1-nishio-6-essais-024a8).
Peut-être abi, si tu en trouves le temps, nous indiqueras-tu ta (tes) solution(s) ? Ce sera forcément moins indigeste que cela.

Cordialement
Cenoman