(a) by representation through the Secretaries of War and the Navy respectively together with their Chiefs of Staff on the Advisory Defence Council; (b) by the existence of a Joint Board consisting of the Chief of Staff, the Deputy Chief of Staff and the assistant Chief of Staff (War Plans Department G.S.), representing the Army, and the Chief of Naval Operations, the Assistant Chief of Naval Operations and the Director, War Plans Division Office of Naval Operations representing the Navy. This Joint Board is responsible for securing co-operation in all matters involving combined action; (c) by the existence of the Joint Planning Committee which is a sub-division of the Joint Board and which studies strategy involving the two services and consists of members of the War Plans Department of the two staffs.