Logic Masters Deutschland e.V.

Rules:

Quattroquadri: Place a digit from 1-9 in each empty cell in the grid such that digits do not repeat in any row, column, or 3x3 box.

Super Friendly: A digit in a super friendly cell matches at least one of the row number (counting top to bottom), column number (counting left to right), box number (counting in reading order), or cell position within a box number (counting in reading order). There are exactly 28 super friendly cells.

Renban: Digits on a purple line must be consecutive.

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Puzzle Link: SudokuPad

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My youtube channel on solving sudoku: Crusader Puzzle