|Since your English is excellent, I wonder if you were an officer, or a KATUSA soldier? In my experience, this was where the ROK Army had its best English speakers.
I was in 2nd Infantry Division, Korea, 1986-87. I did a lot of "Route Reconnaisance"* so I travelled over far more of Korea than the average US soldier and knew it better than most.
*mostly, updating maps. You Koreans were always building new things, and we had to keep changing our plans to keep up. On of our plans showed a Battalion "Assembly Area" downstream of a brand new Dam! Bad. We changed it.