Kakuro (Duplicate) by David Altizio
(This is a bonus “second” puzzle that is not connected to the usual Monday-Saturday week difficulty. In fact, this is around Sunday Stumper difficulty.)
or solve online (using our beta test of Penpa-Edit tools)
Theme: Chi
Author/Opus: This is the 6th puzzle from guest contributor David Altizio.
Rules: Variation of Kakuro Rules. One digit must be duplicated and appear exactly twice in each entry (i.e., group of cells connected horizontally or vertically without any black cells between). All other digits must not repeat within an entry.
Difficulty: 5 stars
Time Standards (highlight to view): Grandmaster = 22:30, Master = 37:30, Expert = 1:15:00
Solution: PDF; a solution video is also available here.
Note: Follow this link for classic Kakuro and this link for Kakuro variations. More Kakuro puzzles can be found in Kakuro and Variations by Serkan Yürekli and in The Art of Puzzles 2.
Oh man, I’m so mad at myself, I had considered this variation when trying to figure out what the second puzzle was, but I made a mistake when trying to solve it and thought it was impossible 🙁
Really good puzzle! When I saw the difficulty, combined with the size, I assumed that I was in for a bifurcation-fest but it actually solves completely cleanly. Particularly cool deduction erfbyivat gur gjraglguerr va gur obggbz evtug.
Thanks for your comments carpenter. I expect solver opinion may vary on this puzzle — it is a pretty difficult form of a less common variation where you can trick yourself into many wrong assumptions. The time standards are accurate, which gives it the 5 star rating. Thanks to David for this interesting Kakuro combination.
I agree with carpenter. Even though it took me almost two hours, I never felt stuck the whole time. This is the kind of hard puzzle I like.
First time I’ve seen this variant, but managed to work my way through bit by bit. 🙂