Congratulations, in order received, goes to George G and Michael Fong II for finding Gumbo in Kyu-Iwasaki-tei Garden!
The grounds were purchased in 1896 by Hisaya Iwasaki, son of Mitsubishi's founder, and also the third president of Mitsubishi.
Hisaya hired British architect, Josiah Conder to design a Western-style mansion and a Swiss-style billiards house. They were built along and with over 20 structures, including Japanese-style structures, and a garden. After WW2, the complex was confiscated by the Supreme Commander of Allied Powers. When returned to Japan, the mansion acted as the Research and Training Institute of the Supreme Court until 1970.
The Western style mansion, Billiards Room, only one Japanese style structures remains.
Not much left of the garden but it is still nice.
In 1961 the Western mansion was recognized an important cultural asset and the whole property in 1999. Lots of renovations going on and it operates as a public museum today.