侍・武士
What the warrior class actually was in the sixteenth century — and which parts of the popular image were invented afterwards.
A samurai in the Sengoku period was a member of the warrior class in the service of a lord. The word derives from a verb meaning "to serve", and service — not swordsmanship, not a code of honour — is the core of the definition.
The Sengoku century is when the samurai reached their military peak and, paradoxically, when the class was least exclusive. Anyone who could fight and find a lord could rise: Toyotomi Hideyoshi, who ended up ruling Japan, was born to a farming family.
Japanese sources use "bushi" for the warrior class in general and "samurai" more narrowly for those in direct service to a lord. English uses "samurai" for both, which is fine as long as you know what the word is covering.
Below the samurai proper were the ashigaru — foot soldiers, often recruited from villages, who made up the bulk of any Sengoku army. In the fifteenth century they were seasonal levies. By the late sixteenth they were increasingly full-time paid troops drilled in spear and gun formations, which is one of the era's most important military changes.
Above the samurai were their commanders and, at the top, the daimyo who held the land everyone else was paid from.
The sword is the emblem, but it was not the main battlefield weapon. Sengoku armies fought primarily with:
Sengoku armour was built from lacquered plates and scales laced together, shaped to be worn on horseback and in mass formations, and it was practical rather than ceremonial. As firearms spread, solid-plate cuirasses became more common because laced scale offered less protection against bullets.
Helmets, on the other hand, became spectacular. Commanders wore towering crests — Date Masamune's crescent moon, Honda Tadakatsu's deer antlers — because being recognisable at a distance was tactically useful and politically valuable.
本多忠勝 · 1548–1610
Ieyasu's most famous warrior, said never to have taken a serious wound in a lifetime of fighting.
井伊直政 · 1561–1602
Commander of the "Red Devils", the scarlet-armoured unit that led Tokugawa attacks.
伊達政宗 · 1567–1636
The one-eyed "Dragon of Oshu" who built Sendai and sent an embassy across the Pacific to Rome.
A daimyo's army was assembled from his direct retainers, each of whom brought men in proportion to the land he held. That obligation was calculated in koku, a measure of rice yield, once Toyotomi Hideyoshi's surveys standardised it.
The consequence is that Sengoku armies were federations. A contingent could leave, refuse to advance, or change sides, and at Battle of Sekigahara several did exactly that. Understanding this makes the great battles far easier to follow.
The idea that samurai were bound by absolute loyalty to a single lord is largely a later construction. In the Sengoku period, retainers changed sides regularly, and doing so was normal rather than shameful when a lord could no longer protect or pay them.
The Sanada family deliberately split itself between both sides in 1600 so the house would survive either result — see Sanada Masayuki and Sanada Nobuyuki. That is how the era actually worked.
Several famous samurai ideas belong to the peaceful Edo period that followed, not to the wars themselves:
The best way into the period is through the people. These are the figures whose careers explain the most.
織田信長 · 1534–1582
Broke the old order and brought roughly a third of Japan under one command before being killed by his own general.
武田信玄 · 1521–1573
The "Tiger of Kai": feared cavalry commander, rival of Uesugi Kenshin, and the one man Nobunaga did not want to face.
上杉謙信 · 1530–1578
The "Dragon of Echigo", who fought Takeda Shingen five times and claimed to fight for justice rather than land.
真田信繁（幸村） · 1567–1615
Died attacking Ieyasu's command post at Osaka in 1615, and was called the finest warrior in Japan by his enemies.
服部半蔵 · 1542–1596
A spear-fighting Tokugawa officer who commanded Iga men — not the black-clad ninja of fiction.
弥助 · dates unknown; recorded in Japan 1579–1582
An African man who arrived with the Jesuits and entered Oda Nobunaga's service in 1581.
Not as a written code during the Sengoku period. The texts that define bushido were written later, during the peaceful Edo period, and the modern Western understanding largely comes from a book published in 1900.
No. The majority of any Sengoku army were ashigaru foot soldiers, many recruited from farming villages, and warrior monks and armed peasant leagues also fought as organised forces.
During the Sengoku period, yes — Toyotomi Hideyoshi is the most famous case. Hideyoshi himself then closed that path with edicts separating warriors from farmers.