#652, June 28 - July 4, 2025: The Weekly 'Unsolvable' Sudoku Puzzle
by Andrew Stuart
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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.
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Discussion...
Post an idea here...
... by: Dieter
Sorry, posted solution to old puzzle 553. Please ignore. my comment here.
... by: Dieter
#553 - populated cells = 22 = 27,2%
basics: %
populated cells = 29 = 35,8%
strategy: try to get hidden pairs or triplets. No solver used.
combinations of C2 = (2,5,6,9) and B6 = (1,3,4,6) as numbers 1,3,5,9 are populated most.
C2 = 5 & B6 = 3 solves.
... by: Envy E
Following previous comment
+5 A3 ( +9 C2 ) +9 C4 +4 B6 +25 C4 C6 +1 C1 +78 C7 C8 ( +2 A8 ) +6 B7 +5 B9
+5 G8 +3 H7 H8 +3 B1 +6 H1 b +5 A1 -5 A3
A3 set to 9 gives a solvable puzzle ( 342 Extreme )
... by: Envy E
Begin where Solver runs out of known solutions
+3 E1 +9 D2 +1 E2 +7 C2 +7 B7 +7 J3 +2 J1 +8 E1 -3 E1
... by: Dieter
#652 - populated cells = 25 = 30,9%
basics: %
strategy: try to get hidden pairs or triplets. No solver used.
combinations of F3 = (3,8,9) and F4 = (4,6,9) as numbers 2,3,6,7,8,9 are populated most.
F3 = 3 solves.
... by: Serban
# 652 Basics to 25
1. Column 2 n=3 e=6 Nc=15 Ns=15 => B2=3 solve
2. Number 7 n=3 e=6 N=20 Nc=17 Ns=10 => B7==G4=7 solve
3.Row A n=3 e=6 Nc=40 Ns=1 => A4=5 A9=3 solve
4.Row F n=4 e=5 Nc=7 Ns=3 => F4=4 & [F3=3 OR F2=9] solve