Today, we can no longer see the pond as it was in the days when it was called the “Nikka Pond”. The Nikka Pond is now concealed beneath the present-day Mohri Pond.

The Roppongi 6-chome district has been developed into a new green area, the Mohri Garden. In developing the new garden, “preservation by burying” was used, in which the bottom of the Nikka Pond was compacted, the surrounding earth was improved, and protective sheeting was installed to make it possible to do archeological studies at some point in the future. This “preservation by burying” approach makes it possible both to provide greenery and water elements to Roppongi Hills while preserving the legacy of history for the future.

(Photo on right) The 4 seasons of Nikka Pond. From the left: Spring, summer, autumn, and winter (from the photo album "Images of Roppongi 6-Chome" by photographer Teruhiko Ito)
(Bottom right image) Cross-sectional view: The remains of Nikka Pond remain undisturbed using the “preservation by burying” method.

The redevelopment district contained many trees that were lovingly cultivated by long-term residents. In redeveloping the area as the Mohri Garden, cherry trees (Yoshino cherry trees), camphor, hackberry, gingko, and other species of trees were kept. Some of the stones in the garden were also reused, with the goal of retaining a sense of the site’s history.

Transplanting the large gingko trees was a particularly challenging job. These were the largest of the trees considered for preservation, so they were transplanted because of their value as historical symbols. A gingko (huge tree with a height of 20 meters, trunk diameter of 4. 66 meters at eye level, and branch spread of 15 meters) was successfully transplanted by preserving the tree in its original shape and protecting it from damage.

(Top right photo) Large gingko tree transplantation work (1994), and the same tree today
(Bottom right image) Planting layout

It was impossible for fire trucks to pass due to the narrow roadway. The way the trees were arranged in Roppongi 6-chome made fire prevention activities externally difficult. Efforts were made to improve the urban environment when TV Asahi developed its plans to build its headquarters. Seventeen years passed since the district’s designation by the city of Tokyo in 1986 as a “redevelopment district”, and in 2003, the neighborhood was reborn as Roppongi Hills.