On the evening of May 15, 1938, the Koken Long Range Monoplane, known as the Kokenki in Japan, landed on a runway in Kisarazu, Chiba Prefecture, to great public acclaim.

The Japanese-made aircraft had just set a new world record for a long-distance nonstop flight, as acknowledged by the Federation Aeronautique Internationale, a Switzerland-based body governing aeronautical world records.

The Kokenki traveled 11,651.011 km in a flight lasting more than 62 hours, breaking the previous record of 10,601.48 km set by a French plane in 1932.