Ii Naomori

Who They Were

Ii Naomori (井伊直盛, いい なおもり) was a samurai of the Muromachi period, born in 1506 and killed on 12 June 1560. He served the Imagawa clan, one of the great warrior houses of central Japan, and headed the Ii family, a warrior lineage based in the province of Tōtōmi. His father was Ii Naomune, and his daughter was Ii Naotora, who succeeded him as head of the clan.

The Ii were retainers rather than lords of the first rank. Their importance in Naomori's lifetime came from service: they fought for the Imagawa, and Naomori died in that service. The family's later fame — as one of the most prominent houses of the Tokugawa shogunate — was built on what happened after his death, largely through his daughter and her adopted heir.

Naomori lived through the closing decades of the Muromachi period, an era of collapsing central authority in which regional warlords fought continuously for land and influence. He was born in Eishō 3 (永正三年), the third year of the Eishō era, which corresponds to 1506. His life spanned the years in which the Imagawa clan expanded across Suruga, Tōtōmi, and Mikawa, and it ended on the battlefield at Okehazama.

Life and Career

Naomori was born into the Ii clan, a warrior family whose name would later be written into the foundation story of the Tokugawa regime. His father, Ii Naomune, preceded him as head of the house. Naomori in turn became head of the Ii and served the Imagawa lords, the dominant power in the region during his adult years.

His career is documented chiefly through his death. In 1560, Imagawa Yoshimoto, the head of the Imagawa clan, marched west toward Kyoto with a large army, aiming to seize the capital and impose his authority on the country. The march took his forces through Owari province, held by the young Oda Nobunaga. On 12 June 1560, Nobunaga attacked the Imagawa camp at Okehazama.

The attack succeeded because it was unexpected. Nobunaga's men advanced through thick fog following heavy rain, and struck the Imagawa position while it was still disordered. Imagawa Yoshimoto was killed in the fighting, and the Imagawa army collapsed. Ii Naomori was killed in the same battle, attempting to protect his lord. He was 54 years old by the birth year recorded for him.

The defeat at Okehazama destroyed Imagawa momentum and made Oda Nobunaga's reputation. For the Ii, it removed the lord they had served and left the clan's leadership to Naomori's daughter, Ii Naotora.

Why They Matter

Naomori matters for two reasons, one immediate and one long-term.

The immediate reason is Okehazama. The battle of 12 June 1560 is one of the decisive turning points of the Sengoku period, the century of civil war that ended only with the unification of Japan at the end of the sixteenth century. A small force under Oda Nobunaga destroyed the army of a far more powerful rival, killing Imagawa Yoshimoto. Naomori was among the Imagawa retainers who died that day, killed while trying to protect his lord. His death places him inside one of the most consequential events in Japanese military history.

The long-term reason is dynastic. Naomori had no son who survived him as heir; the headship of the Ii passed to his daughter, Ii Naotora. She later adopted Ii Naomasa, who became one of the Four Guardian Kings — the most trusted generals — of Tokugawa Ieyasu, and the Ii became lords of Hikone and a pillar of the Tokugawa order. Every later achievement of the Ii clan traces back through Naotora to Naomori. Without his line continuing through his daughter, the Ii of the Edo period would not exist as history knows them.

The Name in Japanese

The name is written 井伊直盛. In kana it is いい なおもり, and in romaji it is Ii Naomori. The family name comes first, as is standard in Japanese; the given name follows.

井 — read i here. This kanji means "well," as in a well for drawing water. It is a common element in Japanese place names and surnames.

伊 — read i here. This kanji is used chiefly in names and in the old name for Italy (伊太利, Itaria). Paired with 井, it forms the surname 井伊, Ii, the name of the clan.

直 — read nao here. This kanji means "straight," "direct," or "honest." It appears frequently in samurai given names, often carrying the sense of uprightness or correctness.

盛 — read mori here. This kanji means "prosperous," "flourishing," or "abundant." It is a very common closing element in warrior names of this period, where it conveys the wish that the bearer's house will thrive.

Put together, the given name 直盛, Naomori, combines "upright" with "prosperous." The surname 井伊, Ii, is a two-character clan name built from two kanji that carry no combined everyday meaning — as is typical of Japanese surnames, which are written with characters chosen for sound and lineage rather than for a phrase.

Legacy

Naomori's legacy runs through his daughter. Ii Naotora succeeded him as head of the Ii clan after his death at Okehazama in 1560, an unusual position for a woman in the warrior society of the time. She in turn adopted Ii Naomasa, who became one of the Four Guardian Kings of Tokugawa Ieyasu — the inner circle of generals on whom Ieyasu relied.

Through that adoption, the Ii line continued into the Tokugawa period and became one of its great houses. The family's rise is inseparable from the battle in which Naomori died: the destruction of the Imagawa at Okehazama cleared the way for the Oda, and after them the Tokugawa, to dominate Japan. Naomori himself is remembered as a retainer who died at his lord's side on that day, and as the father through whom the later Ii clan descends.