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.
... by: Dieter
#692 - initially populated cells: 23 = 28,4 %
No solver used, solver = brain.
basics: J1=7
populated cells: 24 = 29,6 %
Strategy: numbers 2,7,1,8 occur most frequently, combine two cells which reduce possible candidates.
combinations of D7 = (1,7,8,9) and D9 = (1,4,7,8,9)
after basic checks 8 matrices left: D7/D9 = 7/1, 8/1, 1/4, 8/4, 9/4, 8/7, 7/8 and 8/9
D7/D9 = 8/1 solves with D1=6.
Optimization:
D1=6 & D9=1 solve.
... by: Yves
2 from plenty two-cells solutions
B7=9 + G9=3
D1=6 + D9=1
... by: Serban
# 692 J1=7 Basics to 24
1. B2=J5=5 solve
2. B2=5 & E5=3 solve
3. E5=3 & J8=9 solve
4. B2=5 & J8=9 solve
