Japanese Sums with Arrows
(Published on 31. December 2021, 22:24 by mathpesto)
I had a lot of fun constructing a Japanese Sums puzzle recently and I wanted to challenge myself to see if I could create one without any given numbers inside or outside the grid. So here it is; hope you enjoy! If you're feeling stuck, check out my walkthrough of the solution below. Comments and ratings are much appreciated, and please be sure to check out my other puzzles here.
Rules:
Within the main 9x9 grid, normal sudoku rules apply.
Arrows: Numbers along an arrow must sum to the number in the circle.
Japanese Sums: Shade cells within the main 9x9 grid so that the clues outside the grid equal the sums of the digits in contiguous blocks of shaded cells in that row/column. Blocks must be separated by at least one unshaded cell.
(Note: The number of clues for a particular row/column is exactly the number of white cells outside the grid for that row/column. (For example, column 7 has three white cells outside of the grid, so there are exactly three clues for column 7.)
(Also note: Numbers outside the main 9x9 grid don’t have to adhere to normal sudoku rules: they can be greater than 9 (including inside of an arrow’s circle), numbers can repeat in the row/column, etc.
Solve on Penpa+ (thanks Vebby!)
SPOILER ALERT Walkthrough of Solution
SPOILER ALERT Video of Mark Goodliffe's (CtC) Solve
Puzzle:
Solution code: Enter rows 8 and 9
Comments
on 23. May 2023, 08:54 by Bankey
Messed up the first time, and returned after a while. Success:) Needs full focus but a Japanese sum variant is always great fun. Thanks, @ mathpesto :)
on 14. March 2023, 16:57 by dennischen
Lots of fun, thanks for this JS puzzle!
on 24. December 2022, 13:52 by mathpesto
Added penpa+ link
on 20. July 2022, 11:56 by AnnaTh
Had to restart several times. But it was worth it. Thanks for this awesome Puzzle.
on 27. May 2022, 10:25 by Krokant
Not fiendishly difficult, but reeeeally nice. And japanese sums are always great. Terrific puzzle. :)
on 11. April 2022, 17:53 by Mody
Schwer, aber schön
on 24. January 2022, 14:19 by mathpesto
Added link to CtC video
on 16. January 2022, 17:52 by StefanSch
The F-puzzle-versions allows no sums greater than 13. But you will need them to solve the puzzle.
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@StefanSch I haven't found a way to allow that on F-Puzzles when in "solving" mode. My workaround is (just for numbers in the margins that are double-digit) switch to "setting" mode, then Cosmetic Tools --> Text.
on 14. January 2022, 09:00 by sandmoppe
@mathpesto: Thanks! Now I'm looking forward to solve your puzzle. I like Japanese Sums and your puzzle seems to be interesting.
on 13. January 2022, 14:23 by sandmoppe
@mathpesto: Is there a possibility to change the black cells to a printerfriendly grey for people like me, who don't like to solve puzzles online?
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@sandmappe Here's a version with gray cells: https://f-puzzles.com/?id=ybrkf86f
on 2. January 2022, 19:11 by mathpesto
Added walkthrough of solution
