RAT RUN 30: Star Rats
(Published on 18. March 2026, 01:00 by marty_sears)
- Normal sudoku rules apply.
- AIM OF EXPERIMENT: Finkz and Phinx must both reach the cupcakes by finding a path through the maze. The paths must not visit any cell more than once, cross themselves or each other, or pass through any thick maze walls. The paths may not share cells except for where they meet at the cupcake cell.
- 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.
- BOOSTER CELLS: There is one booster cell in every row, column and box, and each contains a different digit. The value of a booster cell equals its digit, plus its row number, plus its column number. Eg: If r7c3 is a booster cell and contains a 6, it will have a value of 16 (7+3+6).
- BLACKCURRANTS: If two cells are joined by a blackcurrant then the value of one is double the value of the other.
- STARFRUIT: The sum of the two values joined by a starfruit is always the same, and must be deduced.
- TEST CONSTRAINT: In this experiment, both rats visit the same number of cells, and the sequence of VALUES along both paths are identical. Eg: If the first five values visited by Finkz are 7, 4, 12, 3, 8 (in that order) then the same must be true for Phinx.
Solution code: Digits not visited by either rat in row 6, from left to right
Comments
yesterday, 14:16 by Agent
Awesome 21-30th installments in the series, and this last one was probably one of my favourites overall!
yesterday, 11:04 by homuroll
Stellar puzzle as usual! One thing I noticed is that the starfruit in box 4 seems to be redundant (the solution is still the same, unless I’ve missed something). I wonder if this was deliberate by Marty to make the solve smoother at the end.
Marty: correct :)
on 19. March 2026, 23:26 by davidz32z
Incredible as always! Unbelievable we've now had 31 of these puzzles and they still feel so unique every time! Marty is truly genius
on 19. March 2026, 07:09 by wuc
Awesome. To me 3.5*. Highest quality every week.
on 19. March 2026, 04:29 by jinkela114514
Surprised to see an 11th puzzle in a phase
on 19. March 2026, 03:54 by LunchEntity
Excellent break-in ... also particularly enjoyed the resolution of the booster squares in boxes 3 and 7.
on 19. March 2026, 02:14 by GG_70
SUM DOES NOT MEAN DIFFERENCE!!!
Took me an hour and a half to figure out the logic but then things moved smoothly the rest of the way
on 18. March 2026, 23:33 by VolpeRosso
While it seemed very daunting at first, that puzzle actually came together for me a lot easier than I expected. As always, delightful logic throughout! Along with some of those wonderful "oh, Marty!" moments :)
on 18. March 2026, 23:01 by firespire
Difficulty ratings are an odd thing I can't even start Marty's 2 star Dutch Flat Mates: Split Ends but I could do this.
I know it is a mathematics thing thing that more than five thousand people can do but to me it's impenetrable together with a lot of 2 star ones one here.
This might take time but I don't equate that with difficulty as long as I can do it so never know how to rate it and just copy other peoples rating.
I think maybe I might have missed something but I followed the same path as Simon.
The differences were for some reason I had the mouse in column 1 coloured as not modified with no good reason but luckily that didn't seem to bypass any logic.
Where he can see a path in his head won't work I physically have to write it out, I do worry it's the forbidden 'bifurcation' but I was just doing the exact checks he was doing just written down.
I can't do things in my head with the same mental agility as him so I benefited having the row column lables setting turned on.
on 18. March 2026, 23:00 by damo_89
Smashed the puzzle in a little over an hour, at no point did I realise that I was building a palindrome or that the title is a palindrome. Attention to detail, me.
on 18. March 2026, 21:23 by jobs2554
Very nice puzzle. I disagree with the difficulty ratings here and found it more of a 2 star puzzle. Very nice implementation of a palindrome line into a rat run as well!
on 18. March 2026, 19:24 by Nairurian
A bit more tricky today, it was far from the one that took me the longest but it was the first one that had me break out Excel to map values.
on 18. March 2026, 18:06 by antiknight
Amazing puzzle! It has some nice deductions.
on 18. March 2026, 17:48 by DonQuichopp
Lovely lovely lovely. Took me little less than 2 hours to solve. Didn't find this one as hard as last weeks. For me it flowed really nicely from deduction to deduction.
Looking forward to CtCs video. This time i feel, I got the right logic quite easily. Thank you once more Marty!
on 18. March 2026, 17:22 by Leodesian
Wow, what an incredible puzzle, and my favourite so far. Lots of great moments where I stopped and appreciated how nifty the logic is.
Also finding that doing the Rat Run series is improving me so much as a solver - thank you Marty!
on 18. March 2026, 17:10 by blackjackfitz
Huzzah!
on 18. March 2026, 17:05 by Fool on Hill
Well, I find some of these puzzles easier than some, but that was a harder one for me, and I went down every blind alley that was to be found ... excellent puzzle.
on 18. March 2026, 16:30 by firespire
Maybe the first Rat Run that people have rated 4 stars that I have been able to complete.
Stuck some letters on the grid, saw a conflict, thought wait a minute I might be able to start this and switched to numbers.
I got all the information I needed from the rules, no hidden idea for me to fail to work out, no need to work backwards or anything.
A bit of brute force less thinking is my solving style, not a criticism of the setter. The skill of Marty to create a very strict solve path is what I love.
I had the row column labels setting on which always helps me and then recording cell value when boosted on the board helped.
I remembered to keep the Sudoku pad url I used as I know Marty Changes them. 1 hour 20 was my time which I think is typical of the ones I can do.
on 18. March 2026, 16:18 by vitaminz
This one is a true masterpiece. Nothing else needs to be said.
on 18. March 2026, 15:56 by AshBrown
Didnt find this one too bad for a change. Great puzzle once again
on 18. March 2026, 15:44 by GeorgeTheToad2
Pure genius. Took longer than two hours and I enjoyed every minute. Amazing.
on 18. March 2026, 15:29 by mscha
Another wonderful new ruleset, one that only makes sense in phase 3.
I had more trouble with this than I should; even when I though I got this, Marty managed to surprise me.
Glad that this isn't the finale yet, may phase 3 live long and happily! :-)
Edit to note: Exactly, alconja! Happened to me as well, and I'm sure we're not the only ones.
on 18. March 2026, 14:14 by alconja
Rat Runs are like plugging in a USB stick: Try one way, prove it doesn't work. Try the other way because that has to be right and ... it doesn't work. Try the first way again and it works. :)
(Well, except that rat runs are fun.)
on 18. March 2026, 13:51 by Franjo
I‘m happy to notice that this episode was NOT the last one of season 3! Again it was a great pleasure to reconstruct the paths of the lovely rat twins. Thank you so much!
on 18. March 2026, 12:39 by lune
My first ever comment as I'm usually more of a silent member, but I had to comment. Each time I open this rat series, I read the rules and think "oh my, no way I'll be able to do this one". But then I start, look harder at the clues, look harder at the rules, think a little... and it just flows.
It’s so smooth every time, and so satisfying. The rules that initially seemed scary somehow start to make sense, and everything just clicks.
I absolutely adore this series. It pushes me to think a bit harder, a bit more outside the box, and in the end when you solve it, you feel smarter and incredibly satisfied.
Thanks so much, Marty, it's a pleasure every time, Wednesday started to be my favourite day for a while now :)
on 18. March 2026, 10:22 by cullenmersch
This took me 3 hours to complete, but was an absolute joy to work through! My partner and I love the opportunity to "feed the girls" every week. We'll be sad to see the series end soon.
on 18. March 2026, 09:24 by dinonugs
When I start with all of these, even when I understand the logic of the paths, I can't see how the digits will disambiguate. And then of course, the puzzle will almost effortlessly put them into place.
on 18. March 2026, 08:52 by Owenx
Mind-blowing as always! However, I kinda guessed where the left rat was supposed to go before I was 100% sure. So hard to resist that temptation lol.
on 18. March 2026, 05:57 by npinguy
To clarify the starfruit rule, are you saying that all starfruits represent the same sum (between their 2 cells)?
Marty: Yes that's right. I have tweaked the wording - is it clearer now?
on 18. March 2026, 05:34 by QuiltyAsCharged
The experiment title reads the same backwards and forwards, just like the path itself!
on 18. March 2026, 04:55 by etoler
And once again, I find myself in awe at the utter and unmatched brilliance of a couple of rats.
...oh, and Marty, too, I suppose. ;)
on 18. March 2026, 02:58 by hamosphere
Loved it.... what was satisfying here is I could predict some of the Marty tricks that were incoming.... only took me 30 rat runs!!
on 18. March 2026, 02:51 by Silverscree
Lovely puzzle once more, and an intriguing story unfolding!
Yes, we all know Marty can set well, but for once I'd like to praise his ability to find a new colour every puzzle!
Marty: haha, I am definitely running out!
on 18. March 2026, 01:53 by arctan
very hard at times until you realize the right question to ask about the paths, and then it becomes incredibly obvious how everything must work (and, as always, it does so in the wonderful ways one would expect from a marty puzzle)
on 18. March 2026, 01:19 by ViKingPrime
This is perhaps the Rat Run I've had the most fun with so far, which is saying a lot. I think we can chalk that up to this being one of the setters favorite constraints. You can feel the sheer joy in every step of this puzzle.
