* Image is for illustrative purposes only.1278-1288Dated Swords of the Late Kamakura Period (Kōan Inscriptions)
Kōan Era
弘安（こうあん）
Kōan (1278–1288) was a nengō of the late Kamakura period. A tachi by Rai Kunitoshi inscribed with the Kōan 1 date is recorded as held by the Tokyo National Museum.
Description
The Nengō "Kōan"
Kōan (弘安) was a nengō of the late Kamakura period, in use from 1278 (Kenji 4, the 29th day of the 2nd month; 23 March 1278 in the Julian calendar) until 1288 (Kōan 11, the 28th day of the 4th month; 29 May 1288 in the Julian calendar). It replaced Kenji in 1278. One theory holds that an epidemic was a factor in the change.
A Dated Tachi
A tachi held by the Tokyo National Museum bears the signature 「国俊」 on the tang and 「弘安元年十二月日」 on the reverse. The museum's record gives the smith as Rai Kunitoshi and the period as Kamakura.
Characteristics of This Era
- Kōan (1278–1288), changed from Kenji on the 29th day of the 2nd month of Kenji 4 (23 March 1278 in the Julian calendar)
- A tachi held by the Tokyo National Museum, signed 「国俊」 on the tang, with 「弘安元年十二月日」 on the reverse