This video was produced by WJF Project.
First of all, I thank J. Crew and all the people who pry for Japan in the world including many of Koreans.
Actually we Japanese, cannot possibly put our thanks into words for you all.
On the other hand, some people who do a quite unusual deed in Korea.
This video was produced for those people, not for the others.
Concerning the issue of the Sea of Japan, I recommend to refer following items.
Wikipedia "A Map of the Myriad Countries of the World"
You can see the word "日本海 " = the sea of Japan in Kunyu Wanguo Quantu (坤輿萬國全圖) by Matteo Ricci in 1602. Just go wikipedia "A Map of the Myriad Countries of the World"; Italian: Carta Geografica Completa di tutti i Regni del Mondo, "Complete Geographical Map of all the Kingdoms of the World".
Sample exhibition: Korean use the name of "Sea of Japan" before annexation of Korea.
https://sites.google.com/site/japanseamerdujapon/Home/korean-use-the-name-of-sea-of-japan-i
In above site, you can recognize many Korean old documents used the name of "the Sea of Japan".
