Battle of Inō

What Happened

On 27 September 1556, two armies of the Oda clan met at Inō in Owari Province, in what is now Nishi-ku in the city of Nagoya. On one side stood Oda Nobunaga, the young head of the clan. On the other stood his younger brother Oda Nobuyuki, who had risen against him with the backing of three senior Oda retainers: Hayashi Hidesada, Shibata Katsuie, and Oda Nobuyasu.

The rebels were defeated. Nobunaga's force held the field, and the three conspirators who had supported Nobuyuki were taken. Rather than execute them, Nobunaga pardoned all three after the intervention of Tsuchida Gozen, the mother of both Nobunaga and Nobuyuki.

The quarrel was not finished. Nobuyuki rose a second time in 1557, and was defeated again; his stronghold, Suemori Castle, was destroyed by Nobunaga's retainer Ikeda Nobuteru. In 1558 Nobuyuki planned a third rebellion. Shibata Katsuie informed Nobunaga of the plot, and Nobunaga, feigning illness to draw close to his brother, assassinated him inside Kiyosu Castle.

Background

The battle belongs to the Sengoku period, the long era of civil war that ran from the fifteenth into the seventeenth century, and it falls within the Muromachi period, dated 1336 to 1573. The year 1556 was the second year of the Kōji era (弘治, こうじ), a reign name used from 1555 to 1558.

The Oda were one of several warrior houses contending for control of Owari, a province on the coast facing Ise Bay. Nobunaga had inherited leadership of the clan, but his authority was not accepted by every member of his own family. Nobuyuki's revolt was an internal challenge, not a war against an outside enemy: brother against brother, with Oda retainers choosing sides.

That retainers of the standing of Hayashi Hidesada and Shibata Katsuie joined the rising shows how unsettled the succession was. Shibata Katsuie in particular would go on to become one of Nobunaga's most trusted commanders, which makes his part in the 1556 rebellion and his later loyalty a striking reversal.

Why It Mattered

Inō settled nothing by itself. Its importance lies in what followed: a sequence of three separate challenges by Nobuyuki across 1556, 1557, and 1558, each of which Nobunaga survived and put down. The destruction of Suemori Castle in 1557 removed a base Nobuyuki could operate from. The assassination at Kiyosu Castle in 1558 removed the challenger himself.

By pardoning Hayashi Hidesada, Shibata Katsuie, and Oda Nobuyasu after Inō, Nobunaga kept experienced commanders inside the clan instead of destroying them. The clemency was owed to Tsuchida Gozen, and it preserved manpower that the Oda would need in the wider wars of the Sengoku period.

For Nobunaga personally, the three-year struggle with his brother was an early test of whether he could hold the headship of the Oda against opposition from within his own household. He emerged from it as the undisputed leader of the clan, and went on to become one of the central figures in the unification of Japan.

The Name in Japanese

The battle is written 稲生の戦い and read いのうのたたかい (inō no tatakai). In romaji the place name is Inō, and the full phrase means "the Battle of Inō".

Breaking it down:

• 稲 — read here as i (part of inō). This kanji means "rice plant" or "growing rice". It is the same character used in 稲妻 (inazuma, "lightning") and 水稲 (suitō, "paddy rice"). It is a very common character in Japanese place names, since rice cultivation shaped where settlements were founded.
• 生 — read here as nō (part of inō). This kanji has a wide range of meanings depending on context: "life", "birth", "to be born", "raw", "fresh". In this place name it carries none of those meanings on its own; it is a phonetic element in the name Inō. The same character appears in 生まれる (umareru, "to be born") and 学生 (gakusei, "student").
• の — written in hiragana, not kanji. This is the possessive and linking particle, equivalent to "of" or "'s". It joins the place name Inō to the noun that follows.
• 戦 — read here as tatakai, the kun reading of the character. It means "war", "battle", or "fight". The same kanji appears in 戦争 (sensō, "war"), 作戦 (sakusen, "military operation"), and 戦国 (sengoku, "warring states").
• い — hiragana, the final syllable of tatakai. Written after a kanji stem, it marks the word as a noun formed from a verb; the verb 戦う (tatakau) means "to fight".

So the structure is: place name (稲生) + linking particle (の) + "battle" (戦い). Japanese battle names follow this pattern constantly — a location plus の戦い — which makes the formula worth memorising, since it unlocks the names of dozens of Sengoku engagements.

Key Figures

Oda Nobunaga — head of the Oda clan and commander of the force that won at Inō. He pardoned the retainers who had opposed him, defeated his brother again in 1557, and had him killed at Kiyosu Castle in 1558.

Oda Nobuyuki — Nobunaga's younger brother and the leader of the revolt. Defeated at Inō in 1556, he rebelled a second time in 1557 and lost Suemori Castle, then planned a third rising in 1558 and was assassinated.

Hayashi Hidesada — Oda retainer who supported Nobuyuki at Inō and was defeated and pardoned.

Shibata Katsuie — Oda retainer who fought for Nobuyuki at Inō, was pardoned, and later informed Nobunaga of Nobuyuki's 1558 plot.

Oda Nobuyasu — Oda retainer who joined Nobuyuki's rising and was defeated and pardoned.

Tsuchida Gozen — mother of both Nobunaga and Nobuyuki. Her intervention secured the pardon of the three defeated conspirators.

Ikeda Nobuteru — Nobunaga's retainer, who destroyed Suemori Castle after Nobuyuki's second rebellion in 1557.