Circle of Fifths
(Published on 18. January 2025, 13:00 by graggle)
Circle of Fifths
NB: This puzzle requires some knowledge of music theory.
- Normal sudoku rules apply.
- The black and white lines represent keys on a piano; one octave from C to C. Each of the piano keys (white or black lines) contains a two-digit number, read from bottom-left to top-right. Starting with 13 in box one (the low C), these two-digit numbers increase by 5 or more from key to key, following the circle of fifths (C-G-D-…) up to 86 in box nine (the high C).
- Digits separated by V sum to 5.
- Cells with a grey square contain even digits.
Solve it on CTC .
If you have any questions regarding the ruleset, please feel free to ask!
Best of luck!
Solution code: Row 9, left to right. Answer should be 9 characters, no spaces.
Comments
on 19. January 2025, 16:27 by Lorena
For the unmusical like myself: the piano keys are in alphabetical order, except your alphabet is weird and starts with a C, then goes all the way to G before looping back to A. Also, it has some extra letters placed between the normal ones. These extra letters are indicated with a b or a # which, respectively, mean that it goes before or after the letter it accompanies. So, for example, F# goes immediately after F and Bb goes immediately before B, but B# doesn’t even exist because reasons. With me so far? Now, the circle of fifths is something you can Google, it looks like a clock but with both inner and outer numbers. Except the numbers aren’t numbers but letters. You need to ignore the ones on the inside and focus on the outer ones. You should see a C at the 12 position of the clock. That’s your starting point, that corresponds to the 13 in the puzzle (the number 13 is random and has no significance). Now you go clockwise in the circle of fifths one hour to see which letter you need to find next, which should be G. Find its position in the keyboard following the weird alphabetical order, that’s your second spot (the second largest 2-digit number after 13). Then look at the circle again, that will tell you where to go next. Continue until you’ve gone all the way around the clock and you’re done, now you know all the music theory needed to solve this puzzle.
PS: If your circle of fifths has two letters in certain positions (like 6 o’clock for example), pick one of them at random, or just find a simpler circle.
on 18. January 2025, 18:10 by graggle
Fixed typo in rules
on 18. January 2025, 18:08 by BenTen
I really like the idea and puzzle design, but it was tricky to keep track of those fifths (even knowing the theory). I found the sudoku to finish off the grid was tricky too. Not one for the faint-hearted! Thanks for setting.
