Normal sudoku rules apply. Each cell in the grid should be coloured blue (for water) or green (for land). For cells containing arrows, the digit in that cell shows how many cells share the same colour with the cell in the given direction, NOT including the arrow cell itself. Note that these same-colour cells need not be connected to the arrow cell. Not all arrows are given. The water occupies a single orthogonally connected region of the grid but no 2x2 area can contain only water cells. An island is an orthogonally connected region of at least 3 land cells. All land cells must be part of islands (so land cells are always in groups of three or more orthogonally connected cells). Islands may touch each other diagonally. Land cells forming any island must contain different digits.