[PAC] Triple Japanese Sums
(Published on 24. October 2025, 19:01 by The Book Wyrm)
This puzzle was created for the third round of the Puzzle Agent Championship (PAC) setting tournament. The prompt was to create a puzzle that involves dividing the grid into three orthogonally connected areas.
Rules:
- Divide the grid into three orthogonally connected areas.
Further divide each area into orthogonally connected 9-cell regions.
Place a digit from 1-9 into each cell. - Digits cannot repeat in a region.
Within an area, digits cannot repeat in a row or column. - Clues outside the grid give the sum of continuous runs of cells in the same area, in order.
? represents an unknown digit (numbers may not have leading 0s).
* represents an unknown amount of clues, including none.
If clues are given for a row/column, all clues are given for that row/column. - A digit on an arrow gives the number of cells in the same region seen in the indicated direction (including itself), where region borders block vision.
For aditional clarity an example of a valid grid has been given.
Penpa link: Click Here
Sudokupad link: Click Here
Solution code: Row 8
Comments
on 6. November 2025, 09:10 by MagnusJosefsson
Fantastic!
on 5. November 2025, 18:59 by kamkam
Very hard but beautiful puzzle. Deserves its 5 stars. The end was brutal.... almost gave up doing the sudoku part
on 3. November 2025, 05:51 by wildbush7
Amazing, I didn't feel any single deduction was unfair but there are plenty of chances to overlook a possibility. Definitely the high end of 5* difficulty for me. Loved it!
on 2. November 2025, 04:15 by Montinox
Mind blowing! Loved it!
on 31. October 2025, 02:57 by Playmaker6174
Cool twist on regular Jsum, with some touch of brilliant madness as expected from yours! I didn’t actually struggle so much on this but being cautious throughout helped a lot, especially for certain parts of the solve x)
on 27. October 2025, 23:27 by Piatato
Great fun, thanks!
on 26. October 2025, 23:10 by The Book Wyrm
I posted the wrong version by accident, apologies for any inconvenience. Fairly small change, only affects the last part of the solve.
on 24. October 2025, 22:15 by Christounet
Awesome puzzle, loved it ! Thanks :)
on 24. October 2025, 21:58 by Agent
Great new twist on Japanese Sums, I loved the geometric arguments in this one!
on 24. October 2025, 21:08 by The Book Wyrm
Fixed example image
on 24. October 2025, 19:49 by JustinTucker
Shouldn't the 5th column of the example read 8 5 10 6?
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You are correct, the example has now been updated.
on 24. October 2025, 19:17 by yttrio
One of the highlights of the round for me! Quite challenging, but some brilliant ideas throughout!
