From The Great Successor: The Divinely Perfect Destiny of Brilliant Comrade Kim Jong Un, by Anna Fifield (PublicAffairs, 2019), Kindle pp. 63-64:
BACK HOME, KIM JONG UN PREPARED TO JOIN HIS OLDER brother at Kim Il Sung Military University, North Korea’s equivalent of West Point. It was their mother’s idea to send them to the military academy, a way to bolster her sons’ claims to succession.
His mother’s ambitions were evident. One of the few photos of them together shows her leaning over the boy she called the Morning Star King as he colored. He is about six years old and dressed in a general’s uniform with four stars on his shoulders.
Kim Jong Un had entered the university named after his grandfather in 2002 and began studying juche-oriented military leadership, the idea that North Korea could act alone to defend itself. It was an important ideological lesson even if it had no basis in reality. North Korea was entirely dependent on China for its stability.
That year was pivotal both for the heir apparent and for the regime.
First, it marked a new chapter for relations between North Korea and the United States—for the worse. At the start of 2002, President George W. Bush labeled North Korea part of an “axis of evil.” Bush declared that, together with Iran and Iraq, North Korea was “arming to threaten the peace of the world.… All nations should know: America will do what is necessary to ensure our nation’s security.”
Just a couple of weeks after that speech, Kim Jong Il officially turned sixty. His birthday was always celebrated with great fanfare in North Korea, but this one was even more important than usual. In Korean culture, a man’s sixtieth is a major milestone. It marks the completion of one sixty-year cycle of the Chinese Zodiac observed in many Asian countries.
In the meantime, Kim Jong Il’s one-time consort, and the mother of Kim Jong Nam, died in Moscow that year. Between that and his milestone birthday, Kim Jong Il’s mortality was clearly on his mind. There were signs of nascent preparation for succession.
For starters, there was a new “mother of the nation,” a name previously reserved for Kim Jong Il’s mother, in the propaganda. The Korean People’s Army issued a sixteen-page pamphlet that year called “Our Respected Mother Who Is Loyal to Our Beloved Supreme Commander Is the Most Loyal among Loyalists.” Songs about “Our Respected Mother” soon began to echo across the North Korean airwaves.
These did not explicitly name Ko Yong Hui, but the cadres could read between the lines and see it was her. She elevated to become the next mother of the nation, an early indication that one of her sons was next in line for the leadership.
So efforts to crown one of her sons were well underway even before Kim Jong Nam’s ill-fated trip to Tokyo Disney, although Ko took advantage of his embarrassing gaffe to push her sons’ case.
Ko Yong Hui knew that she did not have long to lobby for her sons. She was losing her fight against breast cancer.
Kim Jong Un, meanwhile, was throwing himself into his studies at the academy, according to official North Korean accounts. The young man was such a natural at military strategy that he was instructing the instructors rather than learning from them, the state media reported.