The present invention relates to an operation method of an internal combustion engine. The internal combustion engine has a cylinder (2) wherein a combustion chamber (3) is formed which is delimited by a piston (5) journalled to move back and forth. At least one transfer channel (14) is provided which connects the crankcase (4) of the engine to the combustion chamber (3) in at least one position of the piston (5). The engine has a supply channel (13) which opens with a supply channel inlet (11) at the cylinder bore (34). The supply channel (13) is connected to the transfer channel (14) via atleast one piston pocket (22, 42) in at least one position of the piston (5). In order to achieve low exhaust-gas values of the engine, the piston pocket (22, 42) has a distance (a) to a lower edge (27) of the transfer window (15) which is less than the distance (b) to a lower edge (26) of the inlet (11) of the supply channel at bottom dead center of the piston (5).; A method for operating an engine provides that the piston pocket (22, 42) is first connected to the transfer window (15) and then to the supply channel inlet (11) during the upward stroke of the piston (5).