One daughter of North Korea’s dictator is almost as tall as her father and looks like she’s growing up fast — ready to replace him any time, even though she’s believed to be only 12 or 13 years old.

That’s the image projected by Kim Jong-un’s daughter, Ju-ae, as she makes her debut on the global stage, tagging along with her father at the Beijing shindig marking the 80th anniversary of  Communist China’s so-called victory over Japan in World War II.

Ju-ae so far has not said a word in public, but North Korean media has taken to calling her not only “beloved” but also “respected” — the same adjective often applied to her father — and she’s been featured on postage stamps. Clearly, he’s placed her in line ahead of a son born two or three years before her and also another daughter, believed to be three years younger.

Ju-ae, dressed in black when she and her father got off the armored train that took them to Beijing  from Pyongyang, has alternated between solid black and white attire as she traipsed around with him for introductions to the host, President Xi Jinping, and President Vladimir Putin, among 26 foreign leaders who flocked to Beijing for the parade.

She may not have accompanied her father when he sat down privately with Mr. Putin for a lengthy conversation that presumably focused on what more the two leaders can do for one another, but her father and aides should have been tutoring her on the ins and outs of statecraft, educating her for a post that she seems destined someday to fill.

A smoker who packs more than 300 pounds on his five-foot, six-inch, frame, Mr. Kim is only 42, but there’s no telling how long he’ll be around. Ju-ae, first photographed with him three years ago at the launch of an intercontinental missile, has her father’s slightly pudgy cheeks and cheery smile, though she’s yet to be heard saying so much as “Hello.”

Now the question is whether Mr. Kim will take Ju-ae with him for another summit with Mr. Putin, with whom he reportedly talked about meeting again at Moscow. Mr. Kim has promised to send thousands more troops to support the Russians fighting for Ukraine along with a steady flow of artillery shells and missiles and other armaments.

No doubt Ju-ae has excellent teachers, one of whom is North Korea’s foreign minister, Choe Son-hui, seen walking unobtrusively several feet behind her as Mr. Kim and his entourage arrived at Beijing.  

Ms. Choe was named foreign minister in 2022 when Ju-Ae made her debut in public with her father and mother, one-time singer Ri Sol-ju, but she’s known her ever since she was a baby. Fluent in English, Ms. Choe interpreted for an NBA star, Dennis Rodman, when he visited North Korea as Mr. Kim’s guest in 2013 and held the baby in his arms — the first time the world was aware of her existence.

One person who was conspicuously not in the picture at Beijing — and who may not be all that enthusiastic about Ju-ae’s top ranking in the pecking order — was Mr. Kim’s younger sister, Kim Yo-Jong. Colorfully outspoken, full of invective against America and South Korea, Kim Yo-jong has repeatedly issued statements that say in shrill verbiage whatever big brother wants out there but not under his name.

Kim Yo-jong has not said anything about her niece, and she’s not been photographed with her in a ceremonial family shot, much less holding her niece’s hand like the girl’s father. There’s yet to be an open sign of discord, but Kim Yo-jong, having often been reported as a possible successor before her brother began showing off Ju-ae, would seem to have good reason to be a little jealous.

If internecine family rivalry seems far-fetched, no one forgets that Mr. Kim staged a show trial against his uncle-in-law, Jang Song-thaek, at the end of 2013. Having been one of the top lieutenants of Mr. Kim’s father, Kim Jong-il, Jang was executed. Then there was the assassination of his older half-brother, Kim Jong-nam, snuffed by a nerve agent smeared on his face while waiting to board a plane at Kuala Lumpur airport in 2017.

Could a similar scenario play out years from now? In the ups and downs of the history of Korea, North and South, no one’s discounting any possibility.