Battle of Uji

What Happened

On June 20, 1180, a small force under Prince Mochihito and the veteran warrior-monk Minamoto no Yorimasa clashed with Taira clan troops at the Uji River, just south of Kyoto. The battle unfolded after the prince’s plan to raise a nationwide revolt against the Taira was discovered prematurely. The imperial court, dominated by the Taira, moved swiftly to arrest the prince, forcing him and Yorimasa to flee the capital.

The fugitives made for the Byōdō-in Temple, a sprawling Buddhist complex on the eastern bank of the Uji River. Taira cavalry pursued them to the river’s edge. Yorimasa’s men tore up the planks of the Uji Bridge, hoping to slow the enemy, but the Taira horsemen forded the river on horseback and overwhelmed the defenders. Prince Mochihito was captured and killed shortly after the fighting; Yorimasa, wounded and surrounded, committed suicide in the temple grounds.

The battle was brief and one-sided, but it did not end the resistance. News of the prince’s death and his edict calling on the Minamoto clan, temples, and shrines to rise up spread across Japan. Within months, other Minamoto leaders, including Minamoto no Yoritomo in the east, answered the call, and the Genpei War—a five-year struggle between the Taira and Minamoto clans—began in earnest.

Background

By 1180, the Taira clan had dominated the imperial court for two decades. Their leader, Taira no Kiyomori, had placed his grandson on the throne and sidelined rival noble families. Prince Mochihito, a son of the retired Emperor Go-Shirakawa, had been passed over for the throne in favour of Kiyomori’s grandson, and he nursed a deep grievance.

In the spring of 1180, Mochihito and Yorimasa, a respected courtier and poet who had long served the imperial family, hatched a plot. They issued an edict—purportedly in the prince’s name—calling on the Minamoto clan, the warrior families of the eastern provinces, and the great Buddhist temples and Shinto shrines to take up arms against the Taira. The edict was a direct challenge to Kiyomori’s authority, but the conspirators moved too slowly.

The Taira learned of the plot through an informant, likely a retainer who betrayed the prince. Kiyomori ordered Mochihito’s arrest, and the prince fled the capital with Yorimasa and a small band of loyal warriors. Their destination was the Byōdō-in, a fortified temple complex that had served as a refuge for imperial rebels before. The Taira pursued them with a much larger force, and the outcome at the Uji River sealed the conspirators’ fate.

Why It Mattered

The Battle of Uji is conventionally marked as the opening engagement of the Genpei War, the conflict that ended Taira supremacy and brought the Minamoto to power. Although the battle itself was a defeat for the anti-Taira forces, the prince’s edict had already been disseminated, and his death turned him into a martyr for the cause.

The uprising that Mochihito and Yorimasa had hoped to spark did not die with them. In the months after Uji, Minamoto no Yoritomo raised an army in the eastern province of Izu, and other Minamoto leaders followed suit across the country. The Taira, despite their victory at Uji, found themselves fighting a multi-front war that would ultimately destroy them at the Battle of Dan-no-ura in 1185.

The battle also established a pattern for the war: the Taira’s superior numbers and cavalry tactics often won the field, but the Minamoto’s ability to regroup and recruit from the provinces proved decisive in the long run. The Byōdō-in, already famous for its Phoenix Hall, became a symbol of the conflict’s opening tragedy.

The Name in Japanese

The battle is known in Japan by two names. The common English title, “Battle of Uji,” corresponds to 宇治平等院の戦い (Uji Byōdō-in no Tatakai), literally “the Battle of Uji’s Byōdō-in.” The more standard Japanese historical name, however, is 以仁王の挙兵 (Mochihito-ō no Kyohei), meaning “Prince Mochihito’s Raising of an Army.”

The Japanese name 以仁王の挙兵 breaks down as follows:

• 以 (も, mo): “by means of” or “with.” In this word it is read as mo and functions as part of the prince’s name.
• 仁 (ち, chi): “benevolence” or “virtue.” Read as chi here, it forms the second syllable of Mochihito’s name.
• 王 (おう, ō): “king” or “prince.” Read as ō, it marks Mochihito as a member of the imperial family.
• の (の, no): a possessive particle, “of.” Written in hiragana, it links the prince’s name to the action that follows.
• 挙 (きょ, kyo): “to raise” or “to lift up.” Read as kyo, it conveys the act of mustering troops.
• 兵 (へい, hei): “soldier” or “army.” Read as hei, it refers to the armed forces raised for the revolt.

The full reading in kana is もちひとおうのきょへい, and in romaji it is Mochihito-ō no Kyohei. The phrase emphasises the prince’s initiative rather than the battle itself, reflecting how Japanese historiography frames the event as the moment a disgruntled prince sparked a national war.

Key Figures

Prince Mochihito (以仁王, Mochihito-ō) was a son of the retired Emperor Go-Shirakawa. Passed over for the throne, he became the figurehead of the 1180 revolt against the Taira. He was captured and killed at Uji on June 20, 1180, but his edict outlived him and galvanised the Minamoto clan.

Minamoto no Yorimasa (源頼政) was a courtier, poet, and warrior in his seventies at the time of the battle. A veteran of earlier campaigns, he had served the imperial court for decades before joining Mochihito’s plot. He led the defence at the Uji Bridge and died by suicide after the defeat, a death that became a model of warrior honour in later literature.

Taira no Kiyomori (平清盛), though not present at the battle, was the architect of the Taira ascendancy and the man who ordered Mochihito’s arrest. His decision to crush the prince’s revolt quickly backfired, as the edict’s circulation triggered the wider war that ended his clan’s rule.