SudokuWiki.org
Strategies for Popular Number Puzzles
9x9 Solvers
6x6 Solvers
Weekly 'Unsolvable'
Puzzles to Play
Apps
Str8ts
Other
Caution!
Print Version
Page Index

#681, January 17 - January 23, 2026:
The Weekly 'Unsolvable' Sudoku Puzzle

by Andrew Stuart
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
Supporter Members have access to all these puzzles going back to number 1.

Discussion...

Post an idea here...
Your Name or Handle

Your suggestion, idea or question

Please enter the
letters you see:
 arrow		 Enter these letters



Please keep your comments relevant to this puzzle.
Email addresses are never displayed, but they are required to confirm your comments. To state your solve time use the smaller form at the top right of this page. Line breaks and paragraphs are automatically converted ? no need to use <p> or <br> tags.

Saturday 17-Jan-2026

... by: Frans Goosens

#681

Combination 2-digits cells

B9=4 Wrong, Undo calculation
B9=9 No solution, Fixed
C3=6 Wrong, Undo calculation
C3=9 ( C7=6 ) Solved,

Total solving time is : 59 sec.
Number of logical steps is : 7251

Saturday 17-Jan-2026

... by: Dieter

#681 - initially populated cells: 24 = 29,6 %
No solver used, solver = brain.
basics: F1=B8=1; B5=D6=8
populated cells: 28 = 34,6 %
Strategy: numbers 1,8,3,5,7 occur most frequently, combine two cells.
combinations of B7 = (3,4,7,9) and C7 = (3,5,6,9)
B7/C7 = 4/6 solves.
Page created on 03-May-2011, last modified on 30-May-2024.
All puzzles on this site are trademarked and copyright
and cannot be reproduced without permission.
Copyright Andrew Stuart @ Syndicated Puzzles, Privacy, 2007-2026