... by: Tomas
#684 Basic strategies to 26 (C3=1)Bi-digits in Row scope.
C1=5 or 8 leads to contradiction => C4=5 and C9=8
Solve
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#684, February 7 - February 13, 2026:
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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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Discussion...
Post an idea here...Tuesday 10-Feb-2026
Bi-digits in Row scope.
C1=5 or 8 leads to contradiction => C4=5 and C9=8
Solve
Tuesday 10-Feb-2026
... by: Frans Goosens
684Combination 2-digits cells
C6=4 No solution, Undo calculation
C6=6 No solution, Undo calculation
E5=5 No solution, Undo calculation
E5=8 No solution, Undo calculation
H2=3 ( E4=2 ) Solved,
Total solving time is : 19 sec.
Number of logical steps is : 2263
Saturday 7-Feb-2026
... by: Dieter
#684 - initially populated cells: 25 = 30,9 %No solver used, solver = brain.
basics: C3=1
populated cells: 26 = 32,1 %
Strategy: numbers 1,9,2,4 occur most frequently, combine two cells.
combinations of A6 = (2,4,6,9) and A7 = (2,3,4,6)
after basic checks 4 matrices left: A6/A7 = 2/4, 2/6, 9/2 and 9/4
A6/A7 = 2/4 solves with H8=7
Optimization:
A6=2 & H8=7 solve.
Saturday 7-Feb-2026
... by: Yves
correction instead of F1=5 you must read G1=5Saturday 7-Feb-2026
... by: Yves
B4=6 or D6=7 (Serban) ... For the fun we can add F1=5 or G4=7Saturday 7-Feb-2026
... by: Serban
# 684 C3=1 Basics 261. D7=3 solve
2. B4=6 solve
3. D6=7 solve