Easy Peasy Sudoku Advent (01) - Position Sums
(Published on 1. December 2025, 06:00 by Richard)
The main goals of my Sudoku Variants Series are:
Looking back to the series so far, there are a few sudokus that were too hard to be approachable for many players; around 40 of them have a difficulty rating of 4 or 5 stars, and that was not my intention.
So I made a sudoku advent calendar, for which I have chosen 24 of the harder variants and made an easier version of it. I aim for difficulties of 1-2 stars and have written some general and/or specific hints as well. I hope some players will try the original SVS puzzle #278 after solving the advent version.
Position Sums
General hint for this type:
If all three white sums of a block are given, you can calculate the sum of the digits in the remaining three cells in row 3 or column 3. This can effect the possible combinations in the white sum in the first two cells of the relevant row or column.
In column 9 the digits 1 and 3 (sum of 4) have to go in row 7 and 9 (sum of 16). In row 9 columns 8 and 9 contain two digits that add to 6 , which rules out the 3 in R9C9.
- Investigating each variant and explore the intrinsic logic of that type;
- Make an approachable puzzle for a large group of players based on that logic, such that puzzlers have fun solving it and learn something as they do so.
Apply classic sudoku rules.
Digits in the first and second cell from the top and from the left are A and B. Clues outside the grid tell something about A and B:
The sum of A and B is the closest to the grid;
The sum of the digits on positions A and B from that side are also outside the grid, in the grey bar.
Clues in white, grey and placed digits cooperate. If for example R4C5 contains a 6; the white sum in R4 cannot contain a 5, since the sum of 12 cannot contain a 6.
Solution code: Column 5
Comments
on 20. December 2025, 12:54 by Tws
It took some time to get the rules. But in the end it was very exciting to solve this puzzle!
on 9. December 2025, 05:05 by Richard
Fixed minor grammar mistake and added the SVS-number to the link.
on 5. December 2025, 14:48 by walid_tun
amazingly brilliant idea, thanks a lot for this gem
on 3. December 2025, 00:23 by dzamie
Whew! If this is the easier version, I can definitely see how the original was too hard. Very cool ruleset, though, at least once I figured out how it worked :D
on 1. December 2025, 15:24 by Rollo
Das fiel mir nicht leicht. Sicher einfacher als SVS278, aber für Anfänger wohl nicht geeignet.
on 1. December 2025, 14:25 by Klausku
Interesting ruleset. It twisted my brain a little at the start. I‘m curious, what else sudoku advent has in store for us.
on 1. December 2025, 12:52 by marcmees
glad to know that in the expected end of year - overdose of daily puzzles, one definitely will be guaranteed fun to solve. Thanks
on 1. December 2025, 12:45 by wuc
Figured it out quickly even I was new on this rule. Approachable fun 2* to me thx.
on 1. December 2025, 12:11 by HumanBirdsong
This is a lovely puzzle Richard, quite approachable but very enjoyable. Thank you for sharing.
on 1. December 2025, 08:36 by Richard
Fixed typo in solution code.
Sorry for the inconvenience!
on 1. December 2025, 07:16 by Piatato
Lovely puzzle! Looking forward to waking up to these advent gifts each day for a while!
on 1. December 2025, 07:05 by henrypijames
Solution check says my solution is wrong.
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You are right. Fixed now!
