Heavily Fortyfived
(Published on 11. January 2026, 17:38 by marty_sears)
Rules:
Normal sudoku rules apply.
The digit on a fortress is larger than every digit that is orthogonally adjacent to that fortress.
Every fortress contains a different digit.
On a teal index line, the digit in the Nth position along the line (starting from the diamond) indicates the position along the line where the digit N appears. Eg: 3214 would be a valid line; the 1st digit, 3, indicates that the 3rd digit is a 1, and so on.
Solution code: Column 4 reading downwards
Comments
on 17. January 2026, 02:25 by Zinger2099
I have solved your challenging but fun puzzle, and now if you'll excuse me, I'm going to hide in my fortified castle for the next forty-five minutes. :P
on 16. January 2026, 14:01 by LenD
New original combination of the fortresses with the index lines, worked great. Got a bit stuck after mid-way forgetting that the remaining fortresses had to be different
on 15. January 2026, 22:55 by Kainapple
A good fun challenge, hoping this ends up on CTC soon though because I must have missed something!
on 14. January 2026, 22:35 by olc
very nice breakin! took a while to figure out but then everything fell into place.
on 13. January 2026, 23:34 by virus_dave
Yet another gorgeous puzzle from the master. Very smooth the whole way, and each time I felt stuck there was one more subtle little interaction or deduction over yonder to keep me going.
Great fun!
on 13. January 2026, 00:19 by mscha
Very elegant puzzle!
Seemingly impossible at first, but once you finally spot the break-in, it almost solves itself.
on 12. January 2026, 18:02 by sujoyku
Thank you for this fun challenge, Marty!
on 12. January 2026, 15:26 by Klausku
Very nice puzzle with a smooth flow. At first glance it looked quite impossible but turned out otherwise. Thats what I like in Marty`s puzzles. Thanks for sharing!
on 12. January 2026, 14:58 by Franjo
Absolutely amazing! Thank you very much for creating and sharing another one of your puzzle-wonders.
on 12. January 2026, 03:49 by Atticus837
At first this puzzle seemed daunting, like the information given must surely leave you stuck quite early on... But as soon as I actually put down some pencil marks everything just started working, like a row of dominoes from one deduction to the next. Solved in just over 13 minutes. Wonderful construction!
on 12. January 2026, 01:05 by GeorgeTheToad2
Lovely combination. Twenty two minutes of fun.
on 11. January 2026, 23:14 by stranac
I only recently got into variant sudoku, so this was my first full-size puzzle with index lines.
Took me almost two hours, but it was definitely a lot of fun. Probably would have been faster if I hadn't forgotten the fortress rule halfway through the puzzle...
on 11. January 2026, 22:26 by vitaminz
Really cool setup to this one! You may be the foremost expert on index lines
Marty: I would say that is definitely ChinStrap, but thankyou :)
on 11. January 2026, 22:15 by Exigus
Very nice index lines puzzle. I always find them difficult to keep track of but diligent pencilmarking is very effective. Thanks!
on 11. January 2026, 21:32 by ViKingPrime
This had an incredibly easy flow to it, intuitive and natural and satisfying.
on 11. January 2026, 19:34 by philolologue
Officially at that point where I've watched so much CTC that I underestimate my solving capability. Thought at no less than three separate points that there's no way I can solve this and will just have to bifurcate, but decided to give it one last go, and found the breakthrough each time. This was SO much fun, thank you!! Just over half an hour for me!
on 11. January 2026, 19:15 by richcard
Lovely how the lines interact - and a nice "secret" title too!
on 11. January 2026, 18:24 by Prof.Dori
Never would imagine someone could do an interesting puzzle using fortress rule, but here we are with another masterpiece.
