As with many things in the North’s bellicose and reclusive Stalinist government, Mr. Kim’s rationale was a mystery, but there was a hint that the performance might be significant. An article about the performance by North Korea’s official Korean Central News Agency said that Mr. Kim, who took over after the death in December of his father, Kim Jong-il, had a “grandiose plan to bring a dramatic turn in the field of literature and arts this year.”

The footage included a segment with a broadly smiling Mr. Kim — with his marked resemblance to his revered grandfather, Kim Il-sung, the nation’s founder — gesturing like a symphony conductor as he gave guidance on music and art to what appeared to be a half-dozen North Korean reporters busily scribbling in notebooks, one of them in a military uniform. The article on the performance said it featured a band organized by Mr. Kim himself.

Adding to the enigma offered, an unnamed young woman was seated next to Mr. Kim. Speculation about her identity ranged from sister to love interest.

There have been expectations that Mr. Kim, who is believed to be in his late 20s and to have been educated in Switzerland, might try to take his nation in a new direction with some sort of opening to the West. However, he has also at times shown the same rigid defiance as his father.