Growth rings confirm Inuyama Castle keep the oldest in Japan

Asahi -- Apr 20
It may sound trite, but the keep of Inuyama Castle here really was built for keeps.

A tree-ring analysis showed that the three-tiered, four-storied donjon was built between 1585 and 1590, making it the oldest among the nation’s 12 remaining original castle keeps, the municipal board of education said.

The board also said the keep’s four floors were likely constructed successively, although a study conducted during repairs between 1961 and 1965 suggested that the third and fourth levels were added later.

“A significant finding is that the keep already had its upper-floor watchtower when it was built just as it does now,” Kazuyoshi Fumoto, a professor of architectural history at the graduate school of Nagoya Institute of Technology, told a news conference in March.

Commissioned by the education board, Fumoto studied the keep of Inuyama Castle, designated a national treasure, with Takumi Mitsutani, a visiting researcher at the Nara National Research Institute for Cultural Properties, known for its expertise on tree-ring dating.

An analysis of growth rings confirmed that a pillar straddling the first and second floors and a beam supporting the fourth floor were made from Japanese cypress trees cut down in 1585 and 1588, respectively.

The floorboards and other parts of the fourth level were also made from timbers presumed to have been felled between 1585 and 1588.

- Asahi