But wars have fortunately been so infrequent, the information about them has often been so conflicting, and so many results have been due to chance, that, in default of experience, the mere reading of books did not lead to very satisfactory results, except in the case of geniuses; and therefore war problems and war games were devised, in which the various factors of material and personnel were represented, and made as true to life as possible. The _tactical_ games resulting, which naval strategists now play, employ models of the various craft used in war, such as battleships, submarines, etc., and are governed by rules that regulate the movements of those craft on a sort of big chess-board, several feet square, that represents an area of water several miles square. The _strategic_ games and problems are based on principles similar to those on which the tactical games are based, in the sense that actual operations are carried on in miniature; but naturally, the strategical operations cover several hundred miles, and sometimes thousands. The aim of both the tactical and the strategic games is to determine as closely as possible the laws that decide victory or defeat; and therefore, for any country, the material, personnel and operations it should employ. Naturally the results obtained are not quite so convincing as those of actual war or battle; but they are more convincing than can be attained in any other way, as yet devised, especially as many of the operations of the game-board that turn out well in games are tried out afterward by the fleet in peace maneuvers. War games and problems may be compared to the drawings that an architect makes of a house which some one wants to build; the plans and drawings are not so realistic as a real house, but they are better than anything else; and, like the war games, they can be altered and realtered until the best result seems to have been attained, considering the amount of money allowed and other practical conditions.