Eiryaku

Overview

Eiryaku (永暦) was a Japanese era name (年号, nengō; literally "year name") that followed the Heiji era and preceded the Ōhō era. The period spanned from January 1160 through September 1161. The reigning emperor during this time was Nijō-tennō (二条天皇), who sat on the Chrysanthemum Throne throughout the era's duration. Eiryaku belongs to the Heian period (794–1185), a long stretch of Japanese history marked by the imperial court's dominance in the capital at Heian-kyō (modern Kyoto).

What Defined the Era

The Eiryaku era began in the immediate aftermath of the Heiji Disturbance (平治の乱, Heiji no ran), a brief but violent conflict that erupted in late 1159 and concluded in early 1160. The disturbance pitted two rival warrior clans—the Taira (平) and the Minamoto (源)—against each other in a struggle for influence at the imperial court. The Taira, led by Taira no Kiyomori (平清盛), emerged victorious, while the Minamoto leader Minamoto no Yoshitomo (源義朝) was killed in flight. The establishment of the Eiryaku era in January 1160 thus signalled a formal break from the turbulence of the Heiji years and announced a new beginning under the political ascendancy of the Taira clan.

The era's name carried an aspirational meaning, reflecting the court's desire for stability after the recent upheaval. In practice, however, Eiryaku was a period of consolidation rather than dramatic transformation. Taira no Kiyomori used these years to entrench his family's position at court, securing appointments and building alliances that would culminate in his rise to the highest offices of state in the following decade. For Emperor Nijō, the era was marked by efforts to assert imperial authority against the competing interests of the retired emperor Go-Shirakawa (後白河天皇), who had abdicated in 1158 but continued to exercise power through the cloistered emperor system (院政, insei).

Key Events

The most significant event of the Eiryaku era was the conclusion of the Heiji Disturbance's aftermath. In the first months of 1160, Taira no Kiyomori systematically hunted down and executed surviving members of the Minamoto faction who had participated in the uprising. Among those killed was Minamoto no Yoshihira (源義平), Yoshitomo's eldest son, who was captured and executed in the capital. The young Minamoto no Yoritomo (源頼朝), then just thirteen years old, was spared execution and instead exiled to Izu Province—a decision that would have profound consequences decades later when Yoritomo returned to found the Kamakura shogunate.

In the political sphere, Emperor Nijō worked to consolidate his own authority during the Eiryaku years. He promoted loyal courtiers to key positions and attempted to check the influence of his father, the retired emperor Go-Shirakawa. This tension between the reigning emperor and the cloistered emperor defined much of the era's court politics, though it did not erupt into open conflict during Eiryaku itself. The era also saw continued administrative reforms aimed at restoring order to provincial governance, which had been disrupted by the recent fighting.

The Name in Japanese

The era name Eiryaku is written with two kanji: 永暦. In kana, it is read えいりゃく, and in romaji it is rendered as Eiryaku.

The first character is 永, which is read ei (えい) in this word. Its core meaning is "eternal" or "long-lasting." This character appears in common compounds such as 永遠 (eien, "eternity") and 永久 (eikyū, "permanence"). In the context of an era name, 永 conveys the hope that the period will endure peacefully and without interruption.

The second character is 暦, which is read ryaku (りゃく) here. Its meaning is "calendar" or "reckoning of time." This character is central to the Japanese system of tracking years, appearing in words like 暦 (koyomi, "calendar") and 西暦 (seireki, "the Western/Christian calendar"). In era names, 暦 signals that the period is a formally designated unit of time, marked off from what came before and after.

Together, 永暦 can be understood as "eternal calendar" or "lasting reckoning." The name was chosen to express the court's wish that the new era would bring a long and stable stretch of time, free from the chaos that had marked the preceding Heiji years. The pairing of a temporal character (永) with a calendrical character (暦) is typical of Japanese era names, which often combine abstract virtues with references to timekeeping to create a phrase that is both auspicious and administrative.

How the Era Name Works

The Japanese era name system, known as nengō (年号), is a method of dating years by the reign of an emperor or by the proclamation of a new era. Each era name is chosen by the imperial court and announced in an imperial edict. The system was adopted from Chinese practice in 645 CE, during the Taika Reform (大化の改新), and has continued in use—with interruptions—into the modern period.

An era name does not necessarily change when a new emperor ascends the throne. Instead, a new era may be proclaimed to mark a significant event, such as a natural disaster, a military victory, or the beginning of a new imperial reign. The decision to change the era name was often driven by astrological or cosmological considerations, as it was believed that a new era name could reset the spiritual balance of the realm. In the case of Eiryaku, the change from Heiji to Eiryaku in January 1160 came at the start of a new lunar year, a common moment for era renewal.

During the Heian period, era names typically lasted only a few years. The Eiryaku era endured for less than two years, from January 1160 to September 1161, before it was replaced by the Ōhō era. This short duration was not unusual; era names in this period were frequently changed in response to portents, court intrigues, or the simple passage of time. The system remained the official method of dating in Japan until 1873, when the Gregorian calendar was adopted for civil use, though the practice of using era names for imperial reigns continues today in the form of the gengō (元号) system.