Daiei Era
大永（だいえい）
The Daiei era (1521–1528) fell between Eisho and Kyoroku, spanning the transition from Emperor Go-Kashiwabara to Go-Nara and from shogun Ashikaga Yoshitane to Yoshiharu. A dated blade signed "Bizen Kuni Ju Osafune Sukesada, Daiei 3rd year, 2nd month" (1523) survives, documenting continued mass-scale production by the Bizen Osafune Sukesada line during the sue-koto (late old-sword) period.
Description
Daiei as an Era Name
The Daiei era fell between Eisho and Kyoroku, running from August 23, 1521 to August 20, 1528. During this span, the throne passed from Emperor Go-Kashiwabara to Emperor Go-Nara, and the Muromachi shogunate passed from Ashikaga Yoshitane to Ashikaga Yoshiharu. The era change was attributed to warfare and calamity, at a time when Muromachi shogunal authority remained unsettled even within the Kinai region.
A Dated Osafune Sukesada Blade
A blade survives bearing the signature "Bizen Kuni Ju Osafune Sukesada" together with a dated inscription reading "Daiei 3rd year, 2nd month" (1523), providing direct documentary evidence for sword production during the Daiei era. At Osafune in Bizen Province (present-day Setouchi, Okayama Prefecture), a lineage of smiths working under the name Osafune Sukesada, building on forging expertise accumulated since the late Heian period, left numerous works through the late Muromachi period — and the Daiei dating confirms the continuity of this activity.
The Bizen Mass-Production System of the Late Koto Period
From the late Muromachi period through the Sengoku period, Osafune in Bizen was known as one of Japan's largest sword-production centers, overwhelming other regions in both volume and quality — supplying custom-ordered blades (chumon-uchi) for warlords across the country alongside mass-produced blades (kazu-uchi mono) for battlefield demand. The Daiei era represents one cross-section of this Bizen Osafune production system continuing alongside the expansion of Sengoku-period warfare, with the Sukesada-signed dated blade serving as concrete physical evidence.
Position in Sword History
Blades of the Daiei era are rarely discussed in isolation, but the dated inscription offers primary physical evidence for tracing the continuity of Bizen production through the sue-koto period spanning Eisho, Kyoroku, and Tenbun. Apart from stylistic discussions of the Bizen tradition itself, the specific chronological anchor of a dated signature provides material for understanding the production history of the late koto period.
The Naming of Daiei and Its Historical Context
The change to Daiei was carried out in the eighteenth year of Eisho (1521), attributed to warfare and calamity, with the era name itself drawn from a passage in a classical Chinese text — evidence that the court and shogunate still maintained the traditional rites of era-naming at this stage. Even so, the Kinai region during this period remained embroiled in ongoing political strife, including internal conflict within the Hosokawa clan, and effective Muromachi shogunal authority was gradually contracting. Turning to the provinces, sword-producing centers such as Bizen continued to operate according to a logic largely independent of this central political instability, and the Daiei 3 Sukesada signature stands precisely as a dated record of that continuity. The succession of era names from Eisho through Daiei, Kyoroku, and Tenbun overlaps directly with the timeline of the sue-koto mass-production system at Bizen Osafune.
Characteristics of This Era
- Daiei (1521–1528), between Eisho and Kyoroku in the late Muromachi period, spans the transition from Emperor Go-Kashiwabara to Go-Nara and from shogun Ashikaga Yoshitane to Yoshiharu
- A blade signed "Bizen Kuni Ju Osafune Sukesada, Daiei 3rd year, 2nd month" survives, documenting Osafune production activity during the Daiei era
- Late Muromachi to Sengoku-period Osafune in Bizen was one of Japan's largest sword-production centers, producing both custom-ordered and mass-produced blades at scale
- The Daiei era represents one cross-section of this Bizen production system continuing amid the expansion of Sengoku warfare
- The dated signature offers primary physical evidence tracing the continuity of sue-koto Bizen production from Eisho through Kyoroku and Tenbun