In the chaos of the war that left the country divided between a communist north and capitalist south, many families became permanently separated, unable to even communicate by mail or phone, leaving many without information on whether relatives were alive or dead.

On Friday, the sadness inherent in the reunions — which last only a few days and each time end with the families separating again — came into sharp focus. Two of the older participants from South Korea had to leave the reunion held at the Diamond Mountain resort in North Korea early because their health was failing.

One of them, Kim Seom-gyeong, 91, had said he would go to Diamond Mountain to see his North Korean children even if he died there. He made the trip and met his son and daughter. On Friday, South Korean news media ran photos of the North Korean son, Kim Jin-chon, 66, leaning over Mr. Kim in an ambulance to catch his father’s words before he headed home.

Another South Korean, Hong Sin-ja, 84, also had to cut her reunion short.

“I wish I could take her with me,” Ms. Hong was quoted as saying by South Korean pool reports, referring to her North Korean sister, Yong-ok, 82. “Please stay alive until reunification,” the North Korean sister said.