... by: Frans Goosens
#669Combination 2-digits cells
E9=5 No solution, Undo calculation
E9=7 Wrong, Undo calculation
E9=5 No solution, Fixed
A9=4 ( A3=5 ) Solved,
Total solving time is : 41 sec.
Number of logical steps is : 5317
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#669, October 25 - October 31, 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 26-Oct-2025
Combination 2-digits cells
E9=5 No solution, Undo calculation
E9=7 Wrong, Undo calculation
E9=5 No solution, Fixed
A9=4 ( A3=5 ) Solved,
Total solving time is : 41 sec.
Number of logical steps is : 5317
Saturday 25-Oct-2025
... by: BGH
Basics 27.2 #669** 3 Step Solution **
7 @ E4 42.0 Solves for all 7’s
1 @ H9 49.4
— Cell Pair,
— Column 9 Triple
2 @ H4 Solution
— Cell Pair
— Row H Triple
— Column 2 Triple
Dieter's solution matches mine
Saturday 25-Oct-2025
... by: Dieter
#669 - initially populated cells: 22 = 27,2%No solver used.
basics: %
Strategy: Numbers 5,6,7,9 occur most frequently, combine two cells.
combinations of B6 = (1,3,5,6) and B8 = (3,4,6,7)
5 matrices left after basic checks.
B6 /B8 = 5/6 solves with E1=8.
Optimization:
B6=5 & E1=8 solve.
Saturday 25-Oct-2025
... by: Serban
# 669 Basics to 221. J1=1 & G1=6 solve
2. J1=1 & E2=9 solve
3. Number 6 n=3 e=6 N=18 Nc=11 Ns=4 => E6=J7=6 solve
Note : D3=6