The Japan of this time was not a romantic place of sword-wielding knights roaming the countryside looking for adventure. In the sixteenth century the country contained 25 million inhabitants, almost 10% of which were samurai class. This compares to 16 million people in France, and 4.5 million in England. In England about 0.6% of the population were in the warrior class.
Aside from the samurai, Japan's armies of the day also contained a large proportion of peasants, mostly as lightly armed infantry. Warfare at this time was surprisingly modern. At the battle of Nagashino, Oda Nobunaga defeated Takeda Katsuyori, son of the famous Takeda Shigen. In this battle Oda had 38,000 men with 10,000 of them being gunners. 3000 gunners placed across a stream and behind breastworks used 1000 round volley firing to break the famous Takeda Cavalry. The same tactics were seen centuries later in Europe.
Twelve years after Nagashino, at Coutras in France, Henry IV of England won the day using 300 men armed with pistols and squads of 25 gunners. This battle resulted in the largest loss of men to that date in the French civil war with somewhat less than 3000 dead. At Nagashino about 16,000 men died.
In the late 16th century there were more guns in single armies in Japan than existed in all of England. In 1584 the battle of Komaki featured no cavalry attacks at all, and certainly no heroic single combat between samurai. The fight resolved into trench warfare with both sides dug in firing volleys of shot and exploding land mines. Hardly the romantic ideal of sword swinging samurai.
In the 1590s Toyotomi Hideyoshi invaded Korea, originally with 160,000 men (1/4 of which were gunners) and eventually with up to 300,000 men. At about this same time, the daimyo of Japan built their great stone castles and seige warfare became common.
In 1598 Hideyoshi died, leaving an infant heir. Five daimyo were appointed regents and eventually the most powerful, Tokugawa Ieyasu, forced a confrontation to decide who would take supreme power. At Sekigahara Tokugawa fought the forces under Ishida Mitsunari in a battle that involved quite a bit of prior seige work at various castles to control the main roads. Fifteen years later Tokugawa consolidated his power by defeating Hideyoshi's son at Osaka. The country was firmly under his control from this moment on and has remained unified ever since despite the occasional regional rebellion.
Curiously, after Sekigahara there was room once again for the individual heroic warrior. With the coming of the Tokugawa peace the need for mass armies, mass tactics, trenches, and castles disappeared allowing time for individual study of the warrior arts. Most of the existing koryu budo of Japan were developed and refined after 1600.
copyright 2000, Kim Taylor
From Niten Ichi-ryu, a manual of the sword art available from SDKsupplies