South of Imperial Palace and defining the southwestern edge of Ginza is Hibiya Park. The 40 acre greenspace was once owned by the Mōri clan, a powerful dynasty from the 13th century until 1868. The land was also used by the army before becoming a western-style park in 1903 designed by Dr. Honda Seiroku. Surrounding it are a few Tokyo landmarks. One of them is Shisei Kaikan. The terracotta building was constructed in 1929 as the headquarters for the Dōmei News Agency. Two other news companies occupied it after the war. This terracotta building became infamous in 1960 when Inejiro Asanuma, Chairman of the Japan Socialist Party, was assassinated here with a traditional Japanese sword (yoroi-dōshi) during a televised debate. Today, Hibiya Public Hall hosts cultural events plus offices Tokyo Institute of Municipal Research.