Battle of Mimasetōge

What Happened

On 16 November 1569, the army of Takeda Shingen (武田信玄) was marching home through the Sagami highlands when it was ambushed at Mimase Pass by the Hōjō brothers Ujiteru (北条氏照) and Ujikuni (北条氏邦). The Hōjō had placed their forces in the pass itself, where the road narrows and a marching column loses the advantage of numbers. The Takeda vanguard, which included the veteran commander Baba Nobuharu (馬場信春), took the brunt of the attack and was hard-pressed.

Shingen led the Takeda main body into the fight himself. The battle turned when Yamagata Masakage (山県昌景) launched a furious counterattack that broke the Hōjō line and inflicted heavy casualties. The Hōjō army retreated north, and the Takeda were able to continue their march back to Kai (甲斐), their home province. Around 900 men were left dead on the field.

Background

The battle belongs to the Sengoku period (戦国時代), the century and a half of near-constant warfare between regional warlords that ran from the mid-fifteenth century until the country was reunified around 1600. In the formal periodisation used by historians, 1569 falls inside the Muromachi period (1336–1573), named for the shogunate that still nominally governed from Kyoto even as its authority collapsed in the provinces. The year is recorded as the twelfth year of the Eiroku era (永禄), an era name that ran from 1558 to 1570.

The two houses at Mimase were neighbours and rivals in the Kantō region of eastern Japan. Takeda Shingen ruled Kai, the mountainous province west of the Kantō plain. The Hōjō clan, based at Odawara Castle in Sagami Province, controlled much of the plain and the coast. Shingen had been pressing into Hōjō territory, and his campaign culminated in repeated attempts to take Odawara Castle itself. Those sieges failed. With his supply situation deteriorating and the castle holding out, Shingen called off the operation and turned his column westward for home.

The route back to Kai ran through the passes of the Tanzawa and Sagami hills. Mimase Pass was one of the places where a retreating army could be caught at a disadvantage, and the Hōjō chose it deliberately, moving their forces ahead of the Takeda march and lying in wait.

Why It Mattered

Mimasetōge was a fighting withdrawal that succeeded. Shingen had failed to take Odawara, but he brought his army home intact enough to fight again, and the Hōjō paid a heavy price for the attempt to destroy him in the pass. The roughly 900 dead were overwhelmingly Hōjō losses, and the retreat northward left the Takeda road to Kai open.

The result preserved the balance of power in the Kantō. The Hōjō remained a major force, but they had not eliminated their most dangerous western rival, and the Takeda remained free to pursue the conflicts that would define Shingen's final years, above all the long struggle with Oda Nobunaga and Tokugawa Ieyasu. The battle also became a textbook example in later military writing of how a commander extricates an army from hostile ground: the vanguard absorbs the shock, the main body under the lord's personal command holds, and a fresh force delivers the counterstroke.

Among the Takeda commanders present, Baba Nobuharu and Yamagata Masakage were two of the celebrated "Twenty-Four Generals of Takeda Shingen" (武田二十四将), the corps of senior retainers whose reputations were built in campaigns like this one.

The Name in Japanese

The Japanese name is 三増峠の戦い, read in kana as みませとうげのたたかい and romanised as Mimasetōge no Tatakai. The macron over the final e of tōge marks a long vowel: the word is tō-ge, not to-ge.

Broken down character by character:

• 三 — read mi here. The character means "three". It is one of the most basic numerals in Japanese, normally read san in Sino-Japanese compounds, but here it takes the native Japanese reading mi.
• 増 — read mase here. The character means "increase", "grow" or "add to". Its usual Sino-Japanese reading is zō, as in 増加 (zōka, increase). In this place name it supplies the second half of Mimase.
• 峠 — read tōge. This character means "mountain pass", the saddle of high ground where a road crosses a ridge. It is a Japanese-made character (kokuji, 国字) — a character coined in Japan rather than borrowed from Chinese — and it appears constantly in Japanese place names. Its reading here, tōge, is the native Japanese one.
• の — read no. A hiragana particle, not a kanji. It links two nouns, here marking possession or attribution: "the pass of Mimase".
• 戦 — read tataka here, as the first element of the verb-derived noun tatakai. The character means "war", "battle" or "fight". Its Sino-Japanese reading is sen, which is how it appears in compounds such as 戦国 (sengoku, "warring states").
• い — read i. Hiragana, completing the word 戦い (tatakai, "battle"). Written in full, the noun is 戦い; the final i is often dropped in running text, but the name of this battle keeps it.

So the whole name parses as "the battle of Mimase Pass": a place name, the possessive particle, and the word for a battle. Note that the pass itself is written 三増峠, and the location associated with the engagement today is given as the Mimase Tunnel (三増トンネル), the modern road tunnel that carries traffic through the same ground.

Key Figures

Takeda Shingen (武田信玄) commanded the Takeda army. He had led the failed sieges of Odawara Castle and, at Mimase, took personal charge of the main body of his force during the ambush. He returned to Kai after the battle.

Hōjō Ujiteru (北条氏照) was one of the two Hōjō brothers who commanded the ambushing force at the pass.

Hōjō Ujikuni (北条氏邦) was the other brother in joint command of the Hōjō army. Their forces were broken by the Takeda counterattack and withdrew north.

Baba Nobuharu (馬場信春) led troops in the Takeda vanguard, the part of the column that absorbed the initial Hōjō attack and held long enough for the main body to come up.

Yamagata Masakage (山県昌景) commanded the counterattack that decided the battle, driving into the Hōjō line and inflicting the casualties that forced the Hōjō retreat.