... by: Frans Goosens
#674Combination 2-digits cells
G1=6 Wrong, Undo calculation
G1=7 No solution, Fixed
G3=1 ( I1=8 ) Solved,
Total solving time is : 26 sec.
Number of logical steps is : 3065
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#674, November 29 - December 5, 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). |
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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.Share and Enjoy
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Discussion...
Post an idea here...Sunday 30-Nov-2025
Combination 2-digits cells
G1=6 Wrong, Undo calculation
G1=7 No solution, Fixed
G3=1 ( I1=8 ) Solved,
Total solving time is : 26 sec.
Number of logical steps is : 3065
Saturday 29-Nov-2025
... by: BGH
Basics 30.9%2 Step solution
2 @ H2 Cell Pair 27 >> 32.1%
1 @ F2 Cell Pair 17 exposed by step 1 >> Solution
Saturday 29-Nov-2025
... by: Yves
E1=2 And (A1=6 Or B3=2) SolveSaturday 29-Nov-2025
... by: Yves
A1=6 & E=2 SolveSaturday 29-Nov-2025
... by: Dieter
#674 - initially populated cells: 24 = 29,6%No solver used, solver = brain.
basics: H1=4
populated cells: 25 = 30,9%
Strategy: Numbers 4,2,5,6,9 occur most frequently, combine two cells.
combinations of G5 = (5,6,9) and G9 = (1,6,7,9)
3 matrices left after basic checks: G5/G9 = 5/6, 6/9 and 9/1
G5/G9 = 5/6 solve with B8=5
Optimization:
B8=5 & G9=6 solve.
Saturday 29-Nov-2025
... by: Serban
# 674 H1=4 Basics to 251. Column 2 n=4 e=5 Nc=7 Ns=3 => D2=7 solve
Note: H2=2
2. Box 3 ABC123 n=3 e=6 Nc=10 Ns=3 => H3=6 & [G3=1 OR J2=5] solve
3. Number 2 n=3 e=6 N=21 Nc=13 Ns=12 => B3 & [D4 OR E1]=2 solve
Note: H2=2