Subway Marunouchi Line (the last station, change at Nakano-sakaue station to the subway (just in front) to Honancho station.(Get on the front car of the subway) When you get to Honancho, please head for No.1 exit =West Gate. 7 minute-walk from Honancho Station.
or
Metropolitan Bus/Keio Bus: Get off at Kamadera stop. 3 minute-walk to the Hall.