Tonogayato Garden 殿ヶ谷戸庭園（随冝園）
Former Iwasaki villa, the first garden in the Tama area to become a National Monument, in 2011
It opened to the public in 1979, after a residents' movement had called for its protection against a building project. The official cultural properties database (国指定文化財等データベース, bunka.go.jp) dates the 名勝 designation to 21 September 2011, also confirmed by the City of Kokubunji and (read directly in this session) by the operator's official page: ‘殿ヶ谷戸庭園は平成23年9月に国指定の文化財(名勝）となりました’. A ‘1998’ that circulates in some English-language sources (a TripAdvisor box, English Wikipedia) is an error, corrected here.
Tokyo
Kokubunji
