Anyone Read Japanese On This 1939 Cover With Letter?

Hello All,
I've come across this Japanese cover. I'm guessing the date is Showa 14 which makes it 1939. The postmark isn't clear enough to make out the town. Can anyone tell this cover's origin and destination? I've included the letter if there's any hints in there. Also what is the purpose of the purple box handstamp on front? I'm guessing the little red oval handstamp is a mark from the sender, but correct me if I'm wrong please.
Thanks, Will

Update: Facebook friends were able to provide some more information that I'll share here.

"It is from Yongsan, Korea to Ashiya in Hyogo Prefecture. The purple stamp is a "censored" mark; the red seal below is the censoring officer's name, Tanoi."

"The writer writes in a very formal manner to profusely thank the addressee, who has sent a package of care items from Japan. He dwells in particular on the fact that a fan (uchiwa) was the first thing that appeared on opening the package, joking that he is sharing the cool breeze with his mates along with the joy of receiving such fine gifts. He goes on to say that he is well, currently in officers' training while most of the others who arrived with him have already deployed to Shanxi in China, and that he looks forward eagerly to the day he can also join the fighting at the front."

That sure helps make this cover a much more interesting item from a historical point. I had to see how long Japan was in control of Korea's postal service. Japan's sphere of influence started in the 19th Century, but Japan fully took over the system in 1905 through the end of World War II.

Nice work! Battlestamps.

Cover is addressed to Hyogo prefecture,Japan.

As the sender was a member of a military installation, his mails were due to military censorship (Japan was at war with China since 1937).

There was no civilian censorship before October, 1941.