This green corridor is near the site of the Matsu-no-o-roka Corridor which was a long corridor in Edo Castle the floor of which was covered in tatami mats. The walls were decorated with paintings of pine trees (matsu) and plovers.
It was in this corridor that Lord Asano Naganori attacked and wounded a court official named Kira Yoshinaka. As punishment, Lord Naganori was forced to commit ritual suicide. A group of his loyal samurai became masterless upon his death. They planned and plotted for more than a year before the revenge killing of Kira Yoshinaka. The 47 ronin were then forced to commit ritual suicide for murder. This true story was popularized in Japanese culture as emblematic of the loyalty, sacrifice, persistence, and honor that people should preserve in their daily lives. The tale of the Forty-seven Ronin has attained legendary status.
Imperial Palace East Garden