Numbers outside the grid are the sum of the lowest and the highest digits in the first three cells from that side.
Solve online in F-Puzzles (Thanks to Crul!)
Solution code: Column 5, followed by row 5.
on 26. December 2021, 09:10 by Richard
Added link for online solving. Thx Crul!
on 26. December 2021, 02:19 by Hecspeed
Quite an enjoyable puzzle. A joy from the vault
on 25. December 2021, 20:11 by Crul
https://f-puzzles.com/?id=y4ws4jjg
Very nice one.
It was fun, thanks!
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Reply: Thanks for solving this ancient puzzle and the provided link!
on 10. September 2010, 09:22 by miez
Gut zu lösen, Schritt für Schritt, danke, hat Spaß gemacht.
on 4. September 2010, 12:43 by Mody
Wie schön, wenn ein Sudoku ohne nennenswerte T&E lösbar ist :)
on 3. September 2010, 14:58 by Statistica
Sehr hübsch! Danke!