Gando? No! It should be called Yanbian.

Oodog

I think it has to do with the way it sounds in Chinese.  When I hear is spoken in Chinese, it sounds like City of Han.  Now, I don't know how it was written in Chinese.  I think a good way to find out is how it was written during the Ming/Qing period.  Ever since the war, there has been name changes everywhere.  I guess South Korea do not want others in China to think that Seoul is a "Chinese" city.  Fair enough.  I would like to know who the city got that name and how is sounds like City of Han when it is spoken in Chinese.  As I said, the way it is written may give us a clue.

Example.  Peking & Beijing.  In Chinese it is all written the same way, but it is spelled differently (Cantonese/Mandarin dialect was the reason). 

Keep in mind that it was the administration of Seoul, not the government, who asked for it- them being not proficient or aware enough of the history of the name.  I personally won't be bothered having Seoul be called "hancheng", the way New York is pronounced as "Nueva York" in spanish, the way "Nihon" is pronounced "Japan" in english, the way "Netherlands" is called "Holland" in english, the way "United Confederations of Helvetica (something like this)" is called "Swiss," etc etc 

"Han" in Hancheng (It's pronounced as Han - s(e)ong; as a sidenote, during the three kingdom era, it was called Hanyang, and more known that way) is written like this:��.  

"Han" as in the Chinese country, is written like this: ��

As you can see, they don't look the same; meaning that the two have different meanings despite their pronounciation.

When we are talking about Gando/Gendo(Yanbian), we are discussing about this particular region that was named during the conflict era.  Calling it Yanbian would be inappropriate first because we aren't talking about the whole Yanbian province and two because it sounds farfetched to call the conflict according to its current name when the focus is the conflict that has occured years before.

Like you don't call Tang Empire "China" because although Tang predecesses China, it's not entirely China in terms of land and the term China was not used to refer Tang.  The two have different meanings.  Same applies to the situation.

That's what I knew when I was in SK.  In fact, the Chinese character "yang", when it found a word with another character referring to a river or mountain, is usually means "at the north of...". For instance, the Chinese city Luoyang, which used to be the capital of the East Han Dynasty, is at the north of the Luo River. Soeal might first be established at some place north to Han River. For that reason it got the traditional name Hanyang (Hanyeong), and later turned into Hancheng when it became a big city and capital of the country.

The problem is: I often see some Korean still call that place Gando when they are discussing current issues.