The Sudokuland: Divide the grid into regions, each consisting of nine orthogonally connected cells. Each row, column and region must contain the digits 1 to 9 once each. The King’s Palace: The shown region is the king’s palace. It is one of the regions in which the grid has to be divided, and so it contains the digits 1 to 9 once each. The Serpent: Some orthogonally connected cells must be shaded to form a single snake that is one cell wide that does not branch and cannot touch itself, not even diagonally. The snake must contain only odd digits. The Watchtowers: The digit in a watchtower (the squared cells) says how many snake cells are a knight’s move away from that cell. Those snake cells sum to the number placed in the top-left corner of the watchtower. There is a watchtower in every region of the grid, and the snake cannot pass through any watchtower. The Spell: Each region of the grid must contain exactly the same number of snake cells.