A researcher at the Historiographical Institute of the University of Tokyo confirmed that a letter was left showing to his vassals when Nobunaga Oda would attack with a large army in order to capture the current "Ikko-Ikki Nagashima" based in Mie Prefecture. I found out.

Sengoku warlord Oda Nobunaga fought fiercely with the "Ikko-Ikki" that occurred in various places, and in the current "Nagashima Ikko-Ikki" based in Kuwana City, Mie Prefecture, Nobunaga sent a large army to capture it in the third battle. ..

The letter was found and confirmed by Associate Professor Yuki Murai of the Historiographical Institute of the University of Tokyo at an internet auction, and Nobunaga was preparing for the third battle with "Ikko-Ikki Nagashima" in the first year of Tensho. In 1573), it was a letter addressed to Shinsuke Kamada, a vassal who was in a castle near the base of Ikko.

In this, it is shown that the base will be attacked from January to March of the 2nd year of Tensho, which is the following year, and then it is instructed to stay in the castle and strengthen the defense until then.

The red stamp at the end, called the red stamp, has been cut off from the letter, but it was judged to be a letter written by Oda Nobunaga based on the quality of the paper used and the characteristics of the handwriting.

Associate Professor Murai said, "The schedule was delayed for about half a year because we dealt with another Ikko-ikki that occurred immediately after sending this letter, but it can be seen that preparations were steadily progressing. Read Nobunaga's thoughts and strategies. It is a valuable discovery with solvable historical materials. "