LOCKING SYSTEM

Abstract A key is set forth for use in a locking system including the key and a lock cylinder, the lock cylinder including a cylinder core which is journalled in 5 a housing and has a keyway for the introduction of the key, a plurality of tumblers actuable by the key and an additional blocking element movably arranged in a guide passage of the cylinder core and displaceable obliquely or transversely to the direction of insertion of the key into the keyway. The key includes a key blade with a key tip, the key blade 10 including a groove or recess which extends in a longitudinal direction of the key blade from the key tip, a counter-element located completely within the groove or recess, the counter-element arranged in use of the key to cooperate with the additional blocking element so that rotation of the cylinder core relative to the housing can be achieved. The key further 15 includes an abutment element formed by the end region of the groove or recess which establishes the maximum depth of the key into the keyway by contact with an abutment element of the lock cylinder and thereby locates the counter-element in a required position to cooperate with the additional blocking element of the cylinder core of the lock cylinder.