Japanese destroyers were torpedo first, guns second. Just finished reading "Neptune's Inferno" by James Hornfischer, who also wrote "Ghost Ship" and "Last Stand of the Tin Can Sailors". A common theme throughout was the use of torpedos by the Japanese and their effectiveness. Obviously US Destroyers used them as well along with some cruisers. The between the wars BBs had torpedos initially but they were removed long before WW2