Logic Masters Deutschland e.V.

This puzzle was designed for the monthly puzzle prompt of the CTC Discord server in July 2024, encouraging setters to create a puzzle with a tennis-like setting process. Two setters agree on a ruleset, then alternatively add clues to the puzzle, until the puzzle is done. Piatato and I did exactly that. I came up with a broad thematic ruleset that we refined together. After that, it was just pure fun to alternate setting and solving each others clues like this. We’d like to thank fjam for giving us the opportunity to explore this new setting process, which we’ll definitely keep using for other puzzles. We hope you’ll enjoy solving this one as much as we enjoyed making it ! Do try the example first to get a full understanding of the ruleset.

The puzzle :

Play on Penpa

Play on Sudokupad

Rules :

- Normal Sudoku Deconstruction : Fill the grid with 9 non-overlapping 3x3 square regions, such that each region contains the digits 1-9 once each and no digit repeats in any row or column. Cells outside regions do not contain digits.

- Crossing Loop : Draw a single loop travelling orthogonally through the centers of some cells. The loop may visit some cells twice, but must travel straight through such cells each time. The loop can not otherwise self-overlap or self-intersect.

- Japanese Sums / Roller Coaster : Clues to the left of rows indicate the sum of values on horizontal segments of the loop in that row, in the correct order. Clues above columns indicate the sum of values on vertical segments of the loop in that column, in the correct order. If there are clues outside a row/column, all the clues for that row/column are given, with the caveat that a '...' stands for zero or more omitted clues. Note that a segment that is entirely outside any region is listed as a clue with a value of 0.

- Double-Crossers : Digits on cells where the loop crosses itself are doubled in value.

- Cipher : Every distinct letter represents a distinct digit from 0 to 9. A question mark represents any digit. For a double digit number, the first digit cannot be 0.

Example puzzle : (without the cipher) :

Play on Penpa

Play on Sudokupad