9/20 Sky Day

Sky Day (Established in 1940 as "Aviation Day." It was interrupted during the war but revived in 1953. The Civil Aviation Bureau of the Ministry of Transport (now Ministry of Land, Infrastructure, Transport and Tourism) renamed it "Sky Day" in 1992. This is the day in 1911 when the Yamada-shiki airship, developed by Inzaburo Yamada, succeeded in flying around Tokyo in one hour.)