Counterclockwise. or righty tighty lefty loosey. If this is the first time the blades have been off, a gorilla in combination with rust/grass in the bottom threads of the nut can cause some interesting torque to remove the first time. With MTD mowers with the 5/8 or 15/16 socket size I have ran into cases where a 600 lb/ft inpact wouldn't take them off.
