Logic Masters Deutschland e.V.

A collaboration with SamuPiano. We decided to combine the octopus-rules from ThePedallingPianist with the Chess-Lines constraint. There is an example puzzle available further down on the page. Thanks to all the testers. Happy solving!

• Sudoku: Normal Sudoku rules apply.
• Fog: The grid is partially covered in fog. Placing correct digits will clear some of the fog in the grid.
• Octopus:
  • Draw 8 tentacles, all of the same length (in no. of cells) that emanate from the head (r5c5) and reach the edge of the grid, where they stop immediately. Tentacles do not cross or overlap, except at the head. Opposite tentacles are considered as single lines, which have 180 degree rotational symmetry.
  • The Octopus’ four lines are keypad-chess lines: one each of pawn, bishop, knight, and rook.
• Chess Lines: Adjacent digits along a keypad-chess line must be related by the standard movement of its assigned chess piece. No special movements are allowed; this is no pawn capture, en passant, promotion, or double advance. In other words, pawns can only move vertically, and one space at a time. For instance, 2-5-8-5-8 could be a valid pawn line.
• Arm Fragments: Each line in the grid must be part of an arm of the octopus. If given, the number next to the line gives the sum of the cell containing the number and the immediate cell pointed to by the line.

Play On SudokuPad

Example Puzzle

These images show a 5x5 example puzzle (left) and the corresponding solution (middle). All arms have the same length - they take 2 steps on either side of the octopus. The arms are rotationally symmetric - since there is an arm ending in the top-right corner, there must also be an arm ending in the bottom-left corner. The arm on the positive diagonal acts as a bishop (68486). The arms next to it are pawn (41474) and rook (25413). The last arm is a knight (29492). The two cells connected by the 4 clue on the top-right sum to 4 (1+3) and are part of the rook arm (a rook can connect 1 and 3). The last image illustrates why a 1 on a knight-line can only be connected to 6 or 8.

Play the Example Puzzle on SudokuPad.