Original 15th-Century Castle Wall Found in Tokyo

The Mainichi reports that a 400-year-old stone wall standing about 13 feet tall has been uncovered at Edo Castle, which was constructed in the mid-fifteenth century A.D. by Ōta Dōkan, a samurai warrior-poet who eventually became a Buddhist monk.

The historic remnants were excavated at the spot where Sannomaru Shozokan (Museum of the Imperial Collections) is undergoing renovation work, in the East Garden of the Imperial Palace, in Tokyo’s Chiyoda Ward.

The stone walls are not thought to have been repaired since they were first built at the beginning of the Edo period (1603-1867). An official at the Chiyoda Ward Government said the finding “allows us to examine stone wall construction techniques at the time.”

According to the ward government, the stone walls were found near the Imperial Palace’s Otemon Gate.

They run about 16 meters north to south and measure about 4 meters high — or about seven steps. It seems they were part of the stone wall for the water-filled moat, and a band-shaped white line for indicating the water flow at the time remains on its surface. It is believed water went up to the stone walls’ fourth to fifth steps.

Researchers assume the whole stone walls were buried by the mid-1600s, based on the loss of its top, the condition of soil on the structure, and drawings from the time.

The field excavation survey was conducted from November to December 2020. Researchers are examining and analyzing the excavated relics and soil and will summarize the results in the future. The stone walls will be covered with soil again afterwards.

Sannomaru Shozokan is set to greatly expand its storage and exhibition areas and had aimed to open fully to the public in 2025, but the effects of the excavation survey mean a year’s delay is now expected.