Logic Masters Deutschland e.V.

Modular lines: every set of three sequential digits along a line must contain a complete set of residues modulo 3, i.e. one digit from {1,4,7}, one from {2,5,8}, and one from {3,6,9}. Digits on two-cell lines cannot be from the same residue set. Digits may repeat on a line if allowed by other rules.

X-Sums: Numbers outside the grid give the sum of the first X digits in the row or column (starting next to the number outside the grid) where X is the first digit along that row or column.

Every X-sum forms a hidden modular line of length X.

Try the puzzle on the Sudokupad app by Sven Neumann.

Originally published as part of the Modular Lines Competition Pack for Cracking the Cryptic.

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