Normal sudoku rules apply. Anti-king: Cells that are diagonally adjacent may not contain the same digit. Dynamic Fog: The grid is mostly covered in fog. Correctly placing digits will reveal the fog in that cell and possibly other cells. Parity Parity: Beneath the fog is a checkerboard pattern of yellow and blue cells. Each digit appears in one of the colors exactly as many times as its value. For example, 7 will appear either exactly seven times in blue or exactly seven times in yellow.