Kim Jong Eun, according to propaganda described in a recent Chinese magazine article, learned to drive at age 3. By 8, he could safely maneuver dirt roads at 75 mph. As a teenager, he mastered four foreign languages. He is now learning three more.

The emerging biography of North Korea’s new leader, considered fictitious in nearly every country but his own, portrays him as the ultimate quick study, a poet and a marksman, an economics whiz and a military strategist.

The mythmaking is particularly important because Kim Jong Eun, handed power in one of the world’s most secretive nations three weeks ago, has yet to publicly prove his acumen. His life has been turned into a hyper-choreographed showcase for his credibility, and Korea-watchers are scrutinizing his every move: He wears a black double-breasted coat much like his grandfather did. He tours military sites that were his father’s favorites. Even his birthday, on Sunday, will be closely watched.

Analysts aren’t certain which birthday it is — maybe his 28th or 29th; perhaps his 30th — but they think the date could provide new clues about the pace of the succession and the extent to which North Korea is willing to toast its young heir while mourning his father, leader Kim Jong Il, who died Dec. 17. North Korea celebrates the birthdays of Kim Jong Il and founder Kim Il Sung as national holidays. But Jan. 8 hasn’t yet been declared as such.

The birthday serves as the first milepost in Kim Jong Eun’s brief tenure as North Korea’s supreme leader. Just weeks ago, he was a background figure — a trainee with some fancy job titles and an all-powerful dad. Now, after a series of rapid job promotions, he is in charge of a nuclear arsenal and a massive army.

He must also juggle the conflicting interests of the elite circle around him while looking out for the health of the nation. An economic opening could lift one of the world’s most impoverished countries, but it could also lead to calls for a democratic government instead of an authoritarian heir.

U.S. officials concede that they have scant insight into the country’s workings, particularly the small group of Kim family members and military generals who hold power. Still, some clues have emerged about the strategy for guiding the succession, with frequent official references to the “instructions” left behind by Kim Jong Il.

Analysts don’t know whether those instructions are written or recorded, real or invented. But North Korea, in its key New Year’s policymaking editorial, mentioned six times its intentions to carry out the precise instructions of the Dear Leader, allowing not even the “slightest vacillation.” That jibes with the country’s only previous power transfer, following the death of Kim Il Sung in 1994, when Kim Jong Il said that his father’s instructions would serve as the “only guideline for hundreds and thousands of years.”

As North Korea’s state media describes it, Kim Jong Eun is the lone inheritor of his father’s vision. That narrative is aimed at boosting his legitimacy within the nation. But it also limits his ability to create policies that differ from those of the past 20 years, a period during which North Korea funneled money to its military, tested nuclear devices, lashed out against neighboring countries, suffered from chronic food shortages and punished government dissenters by sending them to labor camps.

“Does Kim Jong Eun have power? Can he build consensus? I don’t think we know that,” said Joseph Bermudez, an expert on North Korea and an intelligence analyst at Jane’s Information Group. “The first time something comes up which is not in the playbook which he wants to do, if he’s successful in getting his agenda passed, then we’ll see if he has power.”

So far, though, Kim Jong Eun has shown no indication of breaking from his father’s agenda. Last Sunday, Kim Jong Eun visited a military unit — the 105th Tank Division — that Kim Jong Il had visited almost yearly. During the Korean War, that division led the North’s invasion of Seoul.

During his visit, Kim Jong Eun visited the barracks and posed for photos with service members. A documentary of the trip, later broadcast on the North’s state-run television station, showed Kim Jong Eun gesturing and making comments — but it included no audio of his remarks, just a soaring musical score. Published photos of the visit showed him testing the temperature of running tap water at the military camp, examining a spread of food and checking out an e-library.

“Asking in detail about the use of computers in the e-library,” the state-run news agency reported, Kim Jong Eun said that his father “would have been pleased, if he had looked at them.”

Researcher Liu Liu in Beijing contributed to this report.