Logic Masters Deutschland e.V.

This is part 1 of my 6x6 friendly cells trilogy.
Part 2: The amicable prodigy
Part 3: Pygmy Python

Rules
Normal sudoku rules apply.
The grid is covered in fog. Correctly placed digits will clear the fog around that cell. No guessing is required.
Cells separated by a king's move cannot contain the same digit.
Digits separated by an X sum to 10, and they are ALL given.
In this puzzle, there are exactly 9 "friendly" cells.
A cell is "friendly" if it contains its row, column, or box number.

Play this puzzle on SudokuPad