#619, November 9  November 15, 2024: The Weekly 'Unsolvable' Sudoku Puzzle
by Andrew Stuart

WARNING: This is the Weekly 'Unsolvable' Sudoku, rated above 'Extreme'.
This is currently unsolvable by my solver, except perhaps with trial and error strategies.
Using the solver will not help you. (much).

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Each week a new 'unsolvable' will be published and the previous will be accessible here from this archive section.
If you like very tough puzzles, these are for you.
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Discussion...
Post an idea here...
... by: Serban
# 619 F3=5 F4=3 F7=C9=8 F8=4 A8=2 Basics to 29
1. Box 6 GHJ456 n=3 e=6 Nc=15 Ns=9 => H5=5 solve
2. Number 8 n=5 e=4 N=13 Nc=5 Ns=1 => G2=8 basics to 34
Note : J5=8 => E5=9
... by: Serban
# 619 F3=5 F4=3 F7=C9=8 F8=4 A8=2 Basics to 29
1. Number 6 n=3 e=6 N=30 Nc=77 Ns=50 => H1=B8=6 solve
2. Number 7 n=3 e=6 N=21 Nc=13 Ns=8 => G9=7 & [B8=7 OR E7=7] solve
3. Number 9 n=2 e=7 N=27 Nc=34 Ns=23 => C4=9 & [J2=9 OR G7=9] solve
4. Xchain x=8 => J2<>8 => J2(3,7,9) A5(3,5,9) N=6 Nc=9 Ns=7 => A5=3 J2=9 solve
... by: James Havard
A5=3 with B1=3 gives a singles solution. 40 subs and 23 seconds to get 3 solution subs.
... by: Dieter
#619  basics: row F complete; A8=2; C9=8
strategy: try to get hidden pairs or triplets
combinations of G4 / G9 = (1,2,7) / (1,7,9)
(G4=1 &) G9=7 solve, where G4 gets automatically populated if G9=7.
... by: Frans Goosens
#619
Combination 2digits cells
A4=6 No solution, Undo calculation
A4=9 No solution, Undo calculation
D3=2 Wrong, Undo calculation
D3=3 No solution, Fixed
D7=6 ( E5=9 ) Solved,
Total solving time is : 48 sec.
Number of logical steps is : 6440
... by: Serban
# 619 F3=5 F4=3 F7=C9=8 F8=4 A8=2 Basics to 29
1. Number 1 n=3 e=6 N=12 Nc=4 Ns=3 =>
D2=1 & [C1=1 OR B5==1 OR H9=1 OR G4=1 ]
OR E8=1 & [C1=1 OR B5==1 OR H9=1 OR G4=1 ] solve
2. Number 5 n=4 e=5 N=14 Nc=8 Ns=2 => G1=H5=5 OR H5=J8=5 solve