Logic Masters Deutschland e.V.

• Normal Sudoku rules: Place the digits 1-9 in each row, column and box, without repetitions.
• Kropki-Pairs: On a black dot, one digit is double the other. Digits on a white dot have a difference of 1.
• XV-Pairs: Digits separated by a V sum to 5, digits separated by an X sum to 10.
• Buttons: Constraints placed on the Buttons must be used in a 2-cell domino touching that button. Buttons can be rotated in 90° steps, which moves constraints on a Button from one domino to another. Relative positions of constraints on a Button do not change while rotating.
• Negative Constraint on Buttons: Dominoes touched by Buttons (both domino-cells) that do not have a constraint allocated to them may not match any of the constraints listed above (Kropki- and XV-Pairs). However dominoes not touching Buttons may match these constraints without restriction. So if a Button only contains a single V-clue, None of the other 3 dominoes touching the button may contain digits that add to 5 or 10, be consecutive or one be double the other. Also dominoes with clues never violate negative constraint for different clues. So a white dot may contain a 2-3 pair (which matches a V-clue), a V may be 2-3, a white dot may be 1-2 (which also matches a black dot), etc.

Play Rock Button online on Sudokupad or PuzzleTV (with rotatable Buttons!)

This is an easy 6x6 example puzzle:

Play the 6x6 example online

You can also try an easier puzzle with the same rules: Button Spinner