Logic Masters Deutschland e.V.

Anyone who has ever played a stringed instrument is certainly familiar with a Tuning Fork - the note is "A above Middle C", vibrating at a perfect 440 Hz.

Got that sound of the orchestra warming up in your head? Ok then ... put away the guitar and let's get down to some deviously forked logic!

The Rules:
• Normal Sudoku Rules Apply
• All 3 cells equal distance from the center of the Tuning Fork must sum to the value of the cell in the middle of the Fork (Zipper Line rule - digits can repeat in the sum if allowed by other rules. The 'bulbs' on the end of the handles are for cosmetic purposes only.)
• Purple 'sound waves' must be a set of consecutive digits in any order (Renban rule)
• Digits along the Green 'sound waves' must differ by at least 5 (German Whispers rule)



Solve Online here (right-click and open in new tab):
440 Hz (Cracking The Cryptic)

HINTS: (highlight hidden text to see it)
• The 'center' of the Tuning Forks can be reduced to: (The 4 digits along each leg sum to at least 10. The three legs therefore sum to at least 30, and represent four times the zipper total - this must be greater than 7. So you can start with an 89 pair in the center of the forks.)
• Eliminate digits that can never be on the lower 'handle" of the Tuning Forks. (Digits can repeat from one of the top legs to the bottom handle, but can't repeat on the two top legs since they 'see' each other - this limits the digits below.)
• Find the digits that are required to be on all three 'legs' of both Tuning Forks: (The logic is long and convoluted, but it has been independently confirmed that all three legs on each Tuning Fork need both 1 and 2. These digits can be eliminated from the remainder of columns 234678.)

A very big thank you to 'Fool on Hill' for the thorough testing, wise advice, and exceptional written analysis of the logical solution path!

Leave a comment and let me know how you like it!

Puzzle by David Workman (aka "HalfBakedLunatic")