Changdo Myon is located in North Korean. According to casualties listed in NARA for June 13, 1952 a lot seem to have been members of the 45th Inf. Division. Was your grandfather in this division? Is do you may contact the 45th Inf. Division museum, and they be able to help. I know a few guys who were in the 45th during Korea. I could ask around and see if it rings a bell with them. Good luck.