An original letter believed written by samurai general Akechi Mitsuhide immediately after the "Honno-ji incident" -- in which Mitsuhide forced daimyo Oda Nobunaga to commit suicide on June 21, 1582, to end Nobunaga's pursuit to consolidate centralized power in Japan under his authority -- has been discovered, Mie University professor Tatsuo Fujita has revealed.
It is thought that Mitsuhide wrote the letter as a confidential reply to anti-Nobunaga clique leader Tsuchihashi Shigeharu in present-day Wakayama, with the content covering subjects such as restoration of the Muromachi shogunate. The letter also touches on communication between the 15th shogun of the Muromachi shogunate, Ashikaga Yoshiaki -- who was ousted by Nobunaga -- and Mitsuhide.
Currently, the letter is stored at the Minokamo City Museum in Gifu Prefecture. Apparently, a local resident found the letter in a second-hand bookstore in Kyoto Prefecture before donating it to the museum.
Following the donation, a joint investigation of the letter was carried out by people such as Kazuyuki Torii, the head of the Hosa Library in Nagoya. The investigation concluded that it is highly likely the letter was written, signed and sealed by Mitsuhide, based on factors such as the quality and shape of the paper. It is also believed to have been written on June 12, 1582, exactly 10 days after the Honno-ji incident on June 2 (in the old lunar calendar).
At the time, Yoshiaki was based in present-day Fukuyama, Hiroshima Prefecture, having been ousted from Kyoto. In the letter, Mitsuhide writes that he had already promised Yoshiaki that he would work with the ousted shogun when he returned to Kyoto. It was in response to Shigeharu's notice that he had agreed to cooperate with Yoshiaki.
In addition to the original version, a copy of the letter has been kept at the University of Tokyo. The original letter is 11.4 centimeters long and 56.8 centimeters wide, with extremely fine fold lines. Furthermore, based on the fact that an envelope-like piece of stationery was found with the letter, it is thought that the sender meant for the letter to be confidential.
Commenting on the discovery, Fujita says, "It can be assumed (from this letter) that Mitsuhide wanted to topple Nobunaga, help bring Yoshiaki back to power, and restore the Muromachi shogunate."