'oldest' Edo Castle Stone Wall Found
An approximately 400-year-old stone wall from former Edo Castle has been found on the premises of the Imperial Palace in central Tokyo.
The wall was unveiled to the media on Tuesday. It was discovered as excavation work was being carried out in the palace's eastern garden ahead of the planned rebuilding of an Imperial repository.
The wall is around 16 meters wide and four meters high. It is comprised of about seven layers of stones.
Experts say the technique used to stack up the stones is different from the one used to build the other walls at the castle.
An investigation by Chiyoda Ward found that the wall was built during the early Edo period. Officials say it is probably the oldest of all the walls from Edo Castle that still exist.
They say aside from the top layer most of the structure was probably submerged in water or buried underground.
Expectations are high that the discovery will shed new light on how the castle was constructed and what kind of natural environment existed at the time.
Emperor Naruhito visited the site himself in February.
The wall will be reburied in order to protect it. The Imperial Household Agency plans to modify the design of the new repository and postpone the construction work for about one year.
Professor Emeritus Ono Masatoshi at the National Museum of Japanese History says little is known about Edo Castle's early days. He says the discovery of the wall will open a new chapter of scientific research on the castle's history. He added that the find can also give researchers a glimpse into the period during which the country transitioned from civil war into the Tokugawa Shogunate era.
Ono noted that many of the engraved marks discovered on the stone surfaces could provide information about relations between the Shogunate and the feudal lords.