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

#724, November 14 - November 20, 2026:
The Weekly 'Unsolvable' Sudoku Puzzle

by Richard Kröger, guest compiler
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).

Changes March 2026

Due to the introduction of Forcing Nets many Weekly Unsolvable puzzles can now be solved. I have flagged all the Sudoku ones which are solvable. I am struggling to make any new ones so we'll have to see if the Weekly can continue. The point of the Weekly was to provoke discussion and new ideas, so that is progress. But my solution is unlikely to be optimal so alternatives are welcome.

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 14-Nov-2026

... by: Serban

# 724 E5=7 Basics to 23

1. D5=1 & E4=6 solve

2. C5=6 & J5=9 solve

Saturday 14-Nov-2026

... by: Yves

Key Cell => D5=1 (23 bi cells solutions)

J1=1 And D1=8
J5=9 And D9=6

Saturday 14-Nov-2026

... by: Norman Powell

AS's Solver:
1) Single E5= 7
2) Hidden Pair 2 5 in Box 2 A4 and C6 eliminate 1A4, 1C6, 6C6
3) X-Cycles eliminate 4F3
Forcing Networks 4) 3F3, 5) 4D1, 6) 7C2, 7) 5E2, 8) 1E1, 9) 9E1
Run out of known strategies

My Solver finds a solution during the 4th pass of Forcing Networks.
Single E5=7 [AS#1]
Hidden Pair 2 5 in Box 2 A4 and C6 eliminate 1A4, 1C6, 6C6 [AS#2]
Finned Sword Fish BEH367 with Fin E2 eliminate 4F3 [AS#3, X-Cycles]
Grouped Alternative Inference Chains: eliminate 3F3 [AS#4],
Forcing Networks 1st Pass: 2D1, 9D1 [AS#5], 5D2, 5E2 [AS#7], 7F2
Confined to Box - 5J1
3D Medusa: 1E1 [AS#8], 6E1, 9E1 [AS#9] Can see both colours so eliminate
Forcing Networks 2nd Pass: 1B4, 7C2 [AS#6], 7C3, 8F1
Confined to Box: eliminate 7B8
Forcing Networks 3rd Pass: 2G8, 2E7
Forcing Networks 4th Pass finds a solution after suggesting 4 further eliminations while testing 9D8 for ON.
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