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#648, May 31 - June 6, 2025:
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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). |
Archive
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.Share and Enjoy
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Discussion...
Post an idea here...Tuesday 3-Jun-2025
Monday 2-Jun-2025
... by: Serban
# 648 C5=4 F2=J3=6 Basics to 281. Column 3 n=4 e=5 Nc=6 Ns=4 => D3=9 & [E3=2 OR C3=5] basics to 43
1a. X-chain x=1 => [J1,H8]<>1 => H1=1 solve
Note: A3=7 D3=9 G3=8
, 2. Column 5 n=4 e=5 Nc=8 Ns=5 => F5=2 solve
Note: D5=7
, 3. Column 7 n=3 e=6 Nc=8 Ns=8 => E7=3 & J7=9 solve
Note: A7=5 F7=7 J7=9
, 4. Column 9 n=3 e=6 Nc=8 Ns=8 => A9=9 & D9=4 solve
Note: D5=7
Sunday 1-Jun-2025
... by: Frans Goosens
#648Combination 2-digits cells
A3=7 ( I1=4 ) Solved,
Total solving time is : 14 sec.
Number of logical steps is : 833
Saturday 31-May-2025
... by: Dieter
#648 - populated cells = 25 = 30,9%basics: C5=4; F2=J3=6
populated cells = 28 = 34,6%
strategy: try to get hidden pairs or triplets. No solver used.
combinations of H1 = (1,4,5,8) and H9 = (4,6,9) as numbers 1,4.5,6.8 are populated most.
H1=1 solves.
Saturday 31-May-2025
... by: Serban
# 648 C5=4 F2=J3=6 Basics to 281. Number 1 n=4 e=5 N=16 Nc=10 Ns=1 => J6=1 solve
Note: G7=G8=1
2. Number 4 n=4 e=5 N=16 Nc=8 Ns=8 => D9=J1=4 solve
Note: H4=4
3. Number 7 n=2 e=7 N=19 Nc=11 Ns=6 => G2=H8=7 solve