Are there any acquaintances between North Korea and China in the 1960s and 1970s?

Yes, if you have seen the film and television dramas about the Cultural Revolution and compared the current situation in North Korea, you will find that they are very similar.

My classmate's father went there a few years ago and came back to say that there were still signs and pictures of "revolution" on the street. Students and cadres wear Kim Il Sung's badge on their chests. They need tickets to buy things, and food is rationed.