in 1592 and again in 1598, toyotomi hideyoshi organized invasions of korea using some 9,200 ships. from the beginning of the war in 1592, the supreme commander of hideyoshi's fleet was kuki yoshitaka, whose flagship was the 33 meter-long "nihonmaru". subordinate commanders included wakisaka yasuharu and katō yoshiaki. after their experience in the ōei invasion and other operations against japanese pirates, the chinese and korean navies were more skilled than the japanese. they relied throughout upon large numbers of smaller ships whose crews would attempt to board the enemy. boarding was the main tactic of almost all navies until the modern era, and japanese samurai excelled in close combat. the japanese commonly used many light, swift, boarding ships called "kobaya" in an array that resembled a rapid school of fish following the leading boat. this tactic's advantage was that once they succeeded in boarding one ship, they could hop aboard other enemy ships in the vicinity, in a wildfire fashion.