Logic Masters Deutschland e.V.

This was set for Scojo's Setting Saturday prompts. lmdemasi redeemed this prompt to create an approachable Doppelgänger puzzle.

Thanks to gdc for testing!

Rules:

• Doppelgänger:
  • Fill each cell of the main grid such that every row, column and box contains a 0 and eight different digits from 1-9.
  • No two rows, no two columns, and no two boxes may be missing the same digit.
  • For each 0 in the grid, the digits missing in its row, column, and box must be three different digits.
  • Fill each outer cell with the digit missing from the corresponding row, column, or box.