Busan Metro is the starting point of my travelling history around the world
Though the article is written in Japanse, those days' diary still exists.
(Archive)
http://d.hatena.ne.jp/special-rapid223/20110923#1327723106
It was May 1, 2010.
http://d.hatena.ne.jp/special-rapid223/20100501#1272977055
Then, there weren't platform screen doors in the stations on Busan Metro Line 1.
But, on the extended section, platform screen doors are installed completely.
Busan Metro Line 1 extended from Sinpyeong to Dadaepo Beach
http://www.urbanrail.net/as/kr/busan/busan.htm