Battle of Kiyosu

What Happened

On 4 September 1552, Oda Nobunaga (織田信長, おだ のぶなが) fought and won a battle at Kayazu, a place in Owari province (尾張国, おわり の くに), the region that corresponds to the western half of modern Aichi Prefecture. His opponent was Sakai Daizen (坂井大膳, さかい だいぜん), a senior retainer of the Oda family's Shiba branch. The engagement is remembered as the first battlefield victory of Nobunaga's career.

The fight took place in the twenty-first year of the Tenbun era (天文, てんぶん), during the Muromachi period (室町時代, むろまち じだい), the stretch of Japanese history running from 1336 to 1573. It belongs to the Sengoku period (戦国時代, せんごく じだい), the century of civil war that tore the country apart before it was reunified.

The battle is also known as the Battle of Kiyosu, after Kiyosu Castle (清洲城, きよすじょう), the fortress at the centre of the dispute. Kiyosu stood in southern Owari, and control of it was the prize that brought the two Oda factions to blows at Kayazu.

Background

The Oda were not a single unified house in the mid-sixteenth century. They were a cluster of related branches, each holding castles and lands across Owari, and they fought each other as readily as they fought outsiders. The senior branch, based at Kiyosu, claimed the office of shugodai (守護代, しゅごだい) — deputy military governor — of southern Owari, which gave it formal authority over the province's southern districts.

Nobunaga's father, Oda Nobuhide (織田信秀, おだ のぶひで), had built up power from the family's base in the north of the province, and his death in 1551 left his son, still in his teens, as head of the house. Nobunaga's position was fragile. He faced rivals within his own family, and the Kiyosu branch under Oda Nobutomo (織田信友, おだ のぶとも), the deputy governor of southern Owari, was the most immediate threat.

Sakai Daizen served Nobutomo as a leading retainer and commander. The clash at Kayazu was one episode in the wider struggle between Nobunaga's northern Oda and the Kiyosu Oda for mastery of the province. Nobunaga was fighting not a foreign enemy but his own kin.

Why It Mattered

Kayazu was Nobunaga's first victory. For a young and untested heir, that mattered enormously: it demonstrated to his own retainers and to rival houses that he could command troops and win. In a province where loyalty was contingent on success, a first win helped hold a fragile inheritance together.

The battle also opened the campaign that ended with the destruction of the Kiyosu branch. Nobunaga's struggle against Oda Nobutomo and his retainers, of whom Sakai Daizen was one, was the necessary first step in unifying Owari under a single Oda leader. Without control of the province's south and its principal castle, there was no base from which to move on the wider country.

The victory at Kayazu therefore sits at the very start of the sequence of campaigns that would eventually carry Nobunaga to national power. It is the earliest military success recorded for the man who would go on to end the Sengoku period.

The Name in Japanese

The Japanese name of the battle is 萱津の戦い.

• Kana reading: かやづのたたかい
• Romaji: Kayazu no Tatakai

Broken down character by character:

萱 — read here as kaya. It is the kanji for a type of tall grass, miscanthus or reed, the kind that grows in wet lowland. The character is built from the grass radical 艹 on top and the phonetic component 宣 beneath.

津 — read here as zu (in isolation the character is read tsu). It means a harbour, a crossing point, or a ford — a place where water is crossed. Combined, 萱津 (Kayazu) names a grassy landing or crossing, and it survives as a place name in what is now part of Aichi Prefecture.

の — the possessive particle, written in hiragana. It links the place name to the noun that follows, functioning like the English "of".

戦 — read here as tatakai, from the verb 戦う (tatakau, "to fight"). It means war, battle, or combat.

い — hiragana, completing the reading tatakai, the noun form of the verb "to fight".

So 萱津の戦い means, plainly, "the Battle of Kayazu". The alternative English name, Battle of Kiyosu, comes from the castle at the centre of the conflict rather than from the site of the fighting itself.

Key Figures

Oda Nobunaga (織田信長, おだ のぶなが) — head of the northern branch of the Oda house and the victor at Kayazu. He had inherited leadership of his branch on the death of his father, Oda Nobuhide, in 1551, and this was his first battlefield win. He would go on to dominate central Japan.

Sakai Daizen (坂井大膳, さかい だいぜん) — a senior retainer and commander of the Kiyosu branch of the Oda, serving Oda Nobutomo. He led the force defeated by Nobunaga at Kayazu.

Oda Nobutomo (織田信友, おだ のぶとも) — deputy governor of southern Owari and head of the Kiyosu branch of the Oda. He was Nobunaga's principal rival within the family, and the campaign that began at Kayazu was directed against his position.

Oda Nobuhide (織田信秀, おだ のぶひで) — Nobunaga's father, who had built the northern Oda into a significant power in Owari. His death in 1551 left his young son to defend that inheritance, setting the conditions for the conflict at Kayazu.