Logic Masters Deutschland e.V.

Author's note: I originally wanted to avoid giving any actual numbers in the clues, but anyway I gave up on the idea. That said, I'm still really happy with how the final puzzle turned out. It does indeed require some familiarity with deconstruction.

Rules:

• Deconstruction: Contained within the grid are nine non-overlapping 3x3 square regions, which must be located. Each region contains the digits 1 to 9 once each, such that no digit repeats in any row or column. Cells outside these regions do not contain digits and are assigned a value of zero.
• X-Sum: Clues outside the grid indicate the sum of the first X cells in the direction of the clue, where X is the first non-zero digit encountered in that direction (it is guaranteed that such an X exists).
• Cipher: The clues are ciphered. Each distinct letter from 'HARDEST' represents a different digit from 0 to 9. The notation '[X]' refers to a clue whose ones unit is X. A question mark ('?') represents any digit from 0 to 9; however, for a double-digit number, the first digit cannot be 0. To clarify, a single '?' can represent 0.

For example, [6] can represent 6, 16, 26 and so on and the clues will be valid in 11|XX623XXX479|[1], as 11=6+2+3 and 9+4+7+3+2+6=31.

Solve online:  Penpa  Sudokupad

Enjoy!