Logic Masters Deutschland e.V.

Friends in unknown lands redux (still chaos construction)

(Eingestellt am 5. November 2022, 00:29 Uhr von filuta)

Few months ago I posted here the original version of this puzzle which is now still by far my hardest puzzle and also the most valuable learning moment since I started setting sudokus. The amount of both very positive and very negative feedback really made me thinking about a lot of things including if I shouldn't revisit the puzzle at some point. This revised version keeps the first half of the puzzle almost intact, but the later part is done very differently. I love both versions of the puzzle, but I also think the break-in to the puzzle deserves this somehow more friendly ending, at least in such alternative manner. Needless to say, this version is still a very hard puzzle.

Huge thanks to Samish and Piatato for their test solves and feedback on this version and as always, I will be happy to read your comments. Enjoy the puzzle!


-Standard irregular sudoku rules apply, the regions, however, must be deduced by the solver. Some region borders are given and must be respected.

-All regions are orthogonally connected and are numbered by distinct numbers 1-9. The number of the region corresponds to the digit in its upper left corner (the leftmost cell in the highest row).

-A cell is called friendly, if its digit matches the number of its row, column or region (or more of them simultaneously).

-A border between two regions is friendly, if at least one of its adjacent cells is friendly.

-The number in the upper left corner of the cage shows the sum of the digits in the friendly cells within the cage. Digits may not repeat within a cage.

-The clues outside the grid show the number of the friendly borders in the corresponding row or column.

penpa+ link (answer check on digits and edges)
f-puzzles link
ctc app link

Lösungscode: row 3 and row 9 (without a comma or a space)

Zuletzt geändert am 5. November 2022, 07:51 Uhr

Gelöst von Piatato, Samish, Vebby, polar, Leonard Hal
Komplette Liste


Zuletzt geändert am 20. Dezember 2022, 16:15 Uhr

am 20. Dezember 2022, 03:09 Uhr von Leonard Hal
Very nice!
Thanks a lot!

Zuletzt geändert am 5. November 2022, 16:09 Uhr

am 5. November 2022, 11:32 Uhr von polar
It's a pleasure getting to solve this twice! Very much mission accomplished on your goal of a smoother second half, although it's still a challenging puzzle indeed. Well done for taking on the constructive feedback and turning it into an even better version :)
oh, thanks a lot for your kind words, I'm happy to see you solving it the second time around too.

am 5. November 2022, 07:51 Uhr von filuta
fixed solution code

am 5. November 2022, 00:58 Uhr von Samish
Inventive ruleset, brilliant break-in, clean and fair solve path that uses all the main ideas the ruleset allows, and astounding unfolding to finish, well that sounds like a filuta puzzle!
Very happy to have tested this one, certainly a first step toward trying the daunting original sometime!

am 5. November 2022, 00:38 Uhr von Piatato
Again, what an amazing puzzle! I really enjoyed the first version as well, but this indeed works much more smoothly. Didn't need four months for the break-in this time, so yay! :P

Gelöst:5 mal
Beobachtet:3 mal

Lösung abgeben