RAT RUN 29: Counterbalance
(Published on 11. March 2026, 03:31 by marty_sears)
- Normal sudoku rules apply.
- AIM OF EXPERIMENT: Finkz and Phinx must both reach different cupcakes by finding a path through the maze. The paths must not visit any cell more than once, share cells, cross themselves or each other, or pass through any thick maze walls.
- As well as moving orthogonally, they may move diagonally if there's a 2x2 space in which to do so, but may never pass diagonally through a round wall-spot on the corner of a cell.
- ONE-WAY DOORS: A purple arrow may only be passed through in the direction it's pointing. An arrow always points to the smaller of the two digits it sits between.
- REDCURRANTS: If a redcurrant sits between two digits, one is odd and the other is even.
- TEST CONSTRAINT: In this experiment, any digit on Finkz' path indicates exactly how many times that digit appears on Finkz' path. The same rule applies separately for Phinx' path.
Solution code: Cells visited by Finkz or Phinx in row 9, from left to right
Comments
on 16. March 2026, 23:54 by EDL
I had so much fun solving this. Thank you, Marty!
on 16. March 2026, 14:19 by wuc
Unfolds like a miracle. The deductions must be very precisely executed. Of the hardest to me. Brilliant setting.
on 16. March 2026, 09:14 by DonQuichopp
Wow, this was a hard one for me. A very hard one. Sudoku Pad said 1432 minutes in the end. Wow, didn't think that I'd stick with it so long. But in the end it is so rewarding to say I could solve it. I had to restart thrice though. Hahahahha, complete erase of hours of wrongdoing, hahahahah.
Thank you so much Marty! I love these puzzles so much
on 15. March 2026, 23:16 by Clementi
Another absolute gem, so clever. I think is my favourite Rat Run yet.
on 15. March 2026, 17:30 by MikeMeech
aMAZEing as usual!
on 15. March 2026, 09:10 by gasp141424
Absolutely gorgeous as always. A treat to solve even if it took me longer than I'd care to admit
on 14. March 2026, 22:32 by nunc
Again, very beautiful puzzle. I have a hard time to tell which is my favourite. They are all magnificent in their own right. Thank you so much!
on 14. March 2026, 09:02 by MissAmy254
I’m sure I’ve said this multiple times before, but I think this is my favourite so far :) each deduction is so satisfying, especially after opening the puzzle and wondering how on earth there would be enough information to provide a unique solution
on 12. March 2026, 20:36 by Klausku
That was hard. But very satisfying. I was stuck in mid solve for a long time until I realised that being able to count correctly is very helpful. Thanks again, Marty.
Marty: counting correctly is underrated, I think
on 12. March 2026, 03:30 by etoler
Marty, please, I'm begging you: save some genius for the rest of us.
on 12. March 2026, 01:44 by Atticus837
I don't have much to say that hasn't already been said very well by others, except that this might be the best one yet.
At first glance, a counting circles constraint doesn't look like it could possibly give you enough information without loads of other stuff in the grid, and when you've only got redcurrants and one way doors with it... it looked like it just shouldn't be a puzzle that can exist.
And then (in typical Marty fashion) one idea leads to another until you've been pushed to explore every consequence of the rules to their absolute limit.
Anyone can set a puzzle that uses a variant for the solve, but it takes something more to set a puzzle that makes you explore a variant and feel like you've learned something.
Another absolute banger.
on 11. March 2026, 22:30 by Chaka
Just wow! Again!
on 11. March 2026, 21:11 by sujoyku
Wonderful, wonderful puzzle! I already tested it, but could not resist the temptation to solve it again now that it is out. Thank you very much for classic after classic, Marty!
on 11. March 2026, 21:10 by little_turd
Utterly brilliant and fun to solve!
on 11. March 2026, 18:36 by Nairurian
A good balance between tricky and ”Aha!”, although I’ll have to admit it took quite extensive pencil marking to get to the ”Aha!”.
on 11. March 2026, 14:48 by blackjackfitz
Huzzah!
on 11. March 2026, 14:44 by damo_89
Ouch! 5 stars for this, getting my head around the implications of these constraints was very hard, but very rewarding once it started to slot into place.
on 11. March 2026, 13:43 by mscha
Oof! Easy start, but once you figure out the (approximate) paths, it gets tricky. It took me a long while to spot something to move me forward, but after that it was a pretty smooth solve again.
Very nice!
on 11. March 2026, 13:15 by Franjo
Watching the two rats running in counting circles was a great pleasure! Thank you very much for creating and sharing another wonderful (and quite challenging) episode.
on 11. March 2026, 13:06 by Rab3aron
What a puzzle! it was tough but very rewarding
on 11. March 2026, 12:34 by the_fat_goose
Another banger. Takes some staring to get going, but then flows beautifully.
on 11. March 2026, 11:37 by Fool on Hill
Agree that this is one of the best - cunning and enjoyable. I didn't find it as hard as some comments suggest - as usual the rules repay thought, and once I had done my thinking, the solve flowed nicely.
on 11. March 2026, 11:14 by Guvenistan
Another intimidating yet approachable puzzle. I love how you can initially scare the solver and gently guide them towards the solution. Add to that another wonderful flourish at the end.
on 11. March 2026, 10:04 by smars
Nearly 3h, good thing I woke up early. Very very enjoyable constructing the paths in this one - the bar is high but this might be my favorite rat run so far.
on 11. March 2026, 10:01 by dinonugs
As always, beautiful puzzle.
on 11. March 2026, 06:58 by hamosphere
Tough one this week! about 2hrs for me to solve. There was something I was missing here about a 1/4 of the way in.... !!
on 11. March 2026, 06:28 by antiknight
This one had many original and amazing deductions. One of the best so far!
