1930's National Aviation Society Of Japan Cover

This cover dated 1930 makes me wonder why the National Aviation Society of Japan was writing to the Curtiss Airplane company. Wish the letter was with the cover when it got to me.

You might find this to be an interesting quick read: https://www.centennialofflight.net/...ss/Aero2.htm

Prior to WW 2 Japan's aircraft manufacturing capabilities were relatively limited and they imported many aircraft including some from Curtiss - both newer and older models. By the beginning of the China - Japan war in 1937 and with the US government's support Curtiss was working with the Central Aircraft Manufacturing Corporation (CAMCO) which was located near the Burma border in China, and licensed CAMCO to build Curtiss military aircraft. Bu this time Japan was starting to build very effective military aircraft of their own designs and China needed something to fight back.