Sack Lunch (chaos construction)
(Published on 13. January 2025, 18:38 by jwsinclair)
Sack Lunch, by James Sinclair
Divide the grid into nine orthogonally-connected nine-cell regions, and place the digits 1-9 once in each row, column, and region.
The sum of the digits along an arrow is equal to the digit in the connected circle. Arrows do not cross region borders (i.e. a circle and all cells on all connected arrows must be part of the same region).
A digit in a circle (including an arrow circle) indicates the total number of cells in the same region that can be seen orthogonally, including itself.
Edit: to clarify, region borders block vision.
Play online
This puzzle originally appeared as a bonus puzzle in Artisanal Sudoku, Volume 157, along with a very easy 6x6 with the same ruleset.
Solution code: row five, with a dash ("-") to indicate each region border
Comments
on 5. February 2025, 00:31 by stickx
One of my favourite puzzles. <3
on 31. January 2025, 20:11 by Jensa
Brilliant!
on 20. January 2025, 13:37 by Grecolons
One of the best Chaos I've ver done. Glad I got an "early-access" by being subscribed to your substack.
on 18. January 2025, 00:17 by Voidslime
Loved it!
on 17. January 2025, 14:39 by fitzie
this was closer to a 3 for me, not for difficulty, but for time. such a wonderful puzzle.
on 17. January 2025, 10:38 by puzzlepandit
Enjoyed this. The break-in, flow everything is smooth.
on 16. January 2025, 23:03 by dzamie
I was confused as to why the puzzle links were purple. Glad to see this puzzle again!
on 16. January 2025, 17:35 by jwsinclair
edited to add rule clarification
on 16. January 2025, 06:44 by konjecture
I enjoyed this a lot - any puzzle that involves lots of colouring is great in my book.
My only issue is that the rule about digits in circles isn't clear to me. It seems based on the puzzle itself that 'seeing' is a contiguous ability. Example of what I mean (while trying to be as spoiler-free as possible): R3C1 is N and not N+1 regardless of what happens further in R3 or C1.
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Not totally sure if this addresses your point, but cells can't be "seen" through region borders (e.g. if r3c1 and r3c3 are in the same region but r3c2 isn't, r3c3 isn't included in r3c1's count). I think this is typical for rulesets like this, but I should've clarified from the start.
on 16. January 2025, 00:45 by sacklunch
Wonderful puzzle! Very fun, and a great namesake :)
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Haha, thanks :)
on 15. January 2025, 19:58 by Godrick
This was just pure fun. Very smooth solve and lot of nice logic. Thanks!
on 15. January 2025, 10:50 by nunc
Thanks for sharing this amazing puzzle!
on 15. January 2025, 08:32 by Playmaker6174
Great fun time, even for an approachable CC puzzle x)
on 15. January 2025, 00:49 by dustpan
Very nice! I really enjoy CC, but a lot of them tend to be 4-5 stars so I appreciate the light fare you've offered.
on 14. January 2025, 19:17 by MSDOS
Really clean ruleset, great flow in the solve. Wonderful chaos construction! Thanks James!
on 14. January 2025, 17:00 by MCMCHammer
Enjoyed that puzzle (and the 6x6 mini), a nice ruleset and challenging but not super difficult.
on 14. January 2025, 15:55 by Montikulum
Pleasing and invigorating as always. Cute break-in as well.
on 14. January 2025, 15:36 by GeorgeTheToad2
Thank you James Sinclair for an easier CC but still challenging and exciting at the same time.
on 14. January 2025, 13:20 by Franjo
A perfect introduction for all of you who haven’t yet tried to solve a CC-puzzle! And a wonderful exercise for the others… Thank you, J. S.
on 14. January 2025, 10:21 by Myxo
I didn't know a CC this easy was possible to set without making it overclued or trivial. Truly impressive!
on 14. January 2025, 09:17 by VitP
very nice
on 14. January 2025, 03:41 by MaizeGator
I've been solving some very difficult puzzles lately, which are nice, but there is something so refreshing about an approachable CC.
on 14. January 2025, 02:44 by Big Tiger
First: Very nice! I broke it more times than I can count but was having so much fun I was determined to get it. I may even run overdue on a client project because of it.
Second ... your solution code has two solutions. The puzzle solution is singular but the code for proving it here could be either of two ways.
EDIT: Nope, correction, I see it. The "trouble" is you don't need to solve every single border line to get all the digits in place. Doesn't matter, it was a TON OF FUN and highly recommended.
on 14. January 2025, 02:24 by cg24
my first CC! thank you so much for this lovely puzzle :)
on 14. January 2025, 02:08 by tallcat
Very good intro level CC
on 13. January 2025, 21:57 by wuc
Awesome cc puzzle. Typically very hard is this one approachable but still great fun. Great setting thx.
on 13. January 2025, 21:17 by Chaka
Very beautiful logic, very nice flow, very rewarding solve! Simply a very good setting, thank you!
on 13. January 2025, 20:48 by OGRussHood
A deliciously fun sudoku!
on 13. January 2025, 20:06 by mathpesto
Impressively approachable chaos construction!
