The paper elaborates foundational principles of planning,specifically in the field of container stowage planning.The efforts in methodological development to automatethe process of planning often involve translating theknowledge of planning into a rigid formulation ofmathematical models or logical if-then rules.Two models are developed in order to raise ourunderstanding on planning. The models show fewimportant notions of planning principles: a) planning is aproblem-solving task, which has often more than oneequally feasible solutions, b) capability &speed ofperforming planning task improves in line with the degreeof resemblance of current task to previous known tasks.Those findings are of a great importance to determine thestrategic direction of methodological development toautomate stowage planning. It addresses on howautomatic should be a future intelligent stowage planningtool.