Ōan

Overview

Ōan (応安), also romanized as Ō-an, was a Japanese era name (年号, nengō, lit. year name) of the Northern Court during the Era of Northern and Southern Courts. The era followed Jōji and preceded Eiwa, spanning from February 1368 through February 1375. This period fell within the Muromachi period (1336–1573).

During Ōan, the Northern Court in Kyoto recognized two emperors: Emperor Go-Kōgon (後光厳天皇, Go-Kōgon-tennō) and, from 1371, Emperor Go-En'yū (後円融天皇, Go-En'yū-tennō). The rival Southern Court in Yoshino was headed by Emperor Chōkei (長慶天皇, Chōkei-tennō).

What Defined the Era

The Ōan era sat squarely within the Nanboku-chō, or the Era of Northern and Southern Courts, a decades-long split in the imperial line. Two courts claimed legitimacy: the Northern Court, backed by the Ashikaga shogunate in Kyoto, and the Southern Court, which held the imperial regalia and operated from Yoshino. The era name itself was proclaimed by the Northern Court, meaning that official documents and shogunate records used Ōan, while the Southern Court continued its own era names.

The era began in February 1368, a moment of transition. Ashikaga Takauji, the first shogun of the Muromachi shogunate, had died in 1358, and his son Ashikaga Yoshiakira had succeeded him. Yoshiakira died in December 1367, just before the Ōan era opened. His son, Ashikaga Yoshimitsu, became shogun in 1368 at the age of ten, making the early Ōan years a period of regency and consolidation under the shogunate's senior retainers.

The era also witnessed a shift in the Southern Court's fortunes. Emperor Go-Murakami of the Southern Court died in 1368, and his successor, Emperor Chōkei, took the throne. The Southern Court's military position weakened during these years, as the shogunate pressed its advantage in the provinces.

Key Events

In 1368, the Ōan era opened with the accession of Ashikaga Yoshimitsu as the third shogun of the Muromachi shogunate. Yoshimitsu was only nine or ten years old, and effective power initially rested with the shogunate's deputy, Hosokawa Yoriyuki, who served as regent.

The same year, Emperor Go-Murakami of the Southern Court died. His successor, Emperor Chōkei, continued the Southern Court's resistance from Yoshino, but the court's military capacity had been eroded by years of attrition.

In 1371, Emperor Go-Kōgon of the Northern Court abdicated, and Emperor Go-En'yū ascended the throne in Kyoto. This succession maintained the Northern Court's line of imperial authority under shogunate protection.

Throughout the Ōan years, the shogunate worked to subdue Southern Court loyalists in the western and central provinces. The fighting was sporadic rather than decisive, but the balance of power tilted steadily toward Kyoto. By the end of the era in February 1375, the Southern Court had been reduced to a shrinking enclave, though it would not formally surrender until 1392.

The Name in Japanese

The era name is written 応安 in Japanese.

• Kana reading: おうあん
• Romaji: Ōan (also written Ō-an)

The name breaks down character by character as follows:

• 応 (おう, ō) — "to respond," "to answer," or "to correspond." In this era name, it carries the sense of responding to or answering a call, often interpreted as a response to heavenly will or to the needs of the age.
• 安 (あん, an) — "peace," "tranquility," or "calm." This character is ubiquitous in Japanese era names and appears in many other nengō, such as An'ei (安永) and En'an (延安).

Together, 応安 reads as "Ōan" and conveys the meaning of "responding with peace" or "answering with tranquility." The choice of characters reflects the standard practice of era-name selection: pairing an active or responsive character with a character denoting stability, in hopes that the era would live up to its name.

How the Era Name Works

A Japanese era name, or nengō (年号), is a system of dating by imperial reign periods. The practice began in 645 with the Taika era and continued, with interruptions, into the modern period. Each era name is composed of one or two kanji, and the era begins on the day the new name is proclaimed, often in response to a significant event such as an accession, a natural disaster, or a perceived need for renewal.

During the Era of Northern and Southern Courts, the system became complicated. Both courts issued their own era names, and the same calendar year could be known by two different nengō depending on which court's authority one recognized. The Ōan era name was the Northern Court's designation; the Southern Court used its own era names during the same span of years.

Era names serve more than a dating function. They mark time with a moral or aspirational message, and they are used in official documents, legal records, and historical chronicles. For students of Japanese, era names appear constantly in historical texts, and knowing the era name helps place events in context. The Ōan era, for example, is the frame for the early years of Ashikaga Yoshimitsu's shogunate, a period that set the stage for the later unification of the imperial courts under his rule.