... by: Frans Goosens
#667Combination 2-digits cells
A1=3 No solution, Undo calculation
A1=6 ( H7=1 ) Solved,
Total solving time is : 27 sec.
Number of logical steps is : 3633
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#667, October 11 - October 17, 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...Monday 13-Oct-2025
Combination 2-digits cells
A1=3 No solution, Undo calculation
A1=6 ( H7=1 ) Solved,
Total solving time is : 27 sec.
Number of logical steps is : 3633
Sunday 12-Oct-2025
... by: BGH
2 Step Solution Basics 28.43 @ B2 51.9 Solves all 3’s (Row, Column & Block Unit Pairs)
2 @ C7 100% Solves 2’s for 3 Blocks (Row, Column & Block Unit Pairs)
Dteter, Serban & Yves Solutions Match
Saturday 11-Oct-2025
... by: Dieter
#667 - initially populated cells: 23 = 28,4%No solver used.
basics: %
Strategy: Numbers 2,3,5,8,9 occur most frequently, combine two cells.
combinations of A7 = (2,3,5,7) and A9 = (3,5,9)
4 matrices left after basic checks.
A7 /A9 = 3/9 solve with D8=1.
Optimization:
A7=3 & D8=1 solve.
Saturday 11-Oct-2025
... by: Serban
# 667 Basics to 231. Number 1 n=2 e=7 N=29 Nc=38 Ns=28 => E2=J5=1 solve
2. Number 7 n=2 e=7 N=26 Nc=28 Ns=15 => A8=H1=7 solve
3. A8=7 & A7=3 solve
4. A8=7 & G5=8 solve