Prince Kuni Asaakira became sub-commander of the Yokohama Kaigun Kokutai on December 1st, 1938 and is seen here in this photo, from a vintage magazine, in front of a Kawanishi H6K "Mavis" and Hiro H4H2 flying boat. For more on Prince Kuni, here. Note the ladder used by members of the "Mavis" crew to get into the flying boat.
Some cultural information. All members of the Japanese Imperial family get the suffix "nomiya" after their name to denote that they belong to this family. So Prince Kuni in Japanese was called Kuni-nomiya. The heir apparent to the Imperial throne is called Hiro-nomiya*.
Also, in Japan the 124th Emperor is never called "Emperor Hirohito". That was his personal name before he received the title. In Japan he is known as "Showa Tenno" (Emperor Showa).
Finally, the suffix to properly address the Japanese Emperor or Empress is "heika" meaning His/Her Imperial Majesty. For other members of the family it is "denka" meaning His/Her Imperial Highness.
*Funny enough "hironomiya" in Greek means "gesture".