Editor's note: Xu Fangqing is a senior editor at China News Week and an observer of affairs in the Northeastern Asia and China's neighboring countries. The article reflects the author's views, and not necessarily those of CGTN.

The appearance of DPRK leader Kim Jong Un, who inaugurated a fertilizer plant on May 1, according to the Korean Central News Agency (KCNA), has finally quelled global speculation over his health since his absence from public event almost 20 days ago.

However, where the leader's sister Kim Yo Jong sat during the inauguration is worth more attention than the "reappearance" of Kim Jong Un.

It's not rare at all for the DPRK's leaders to be absent from public eye for some time and most people in the country have been used to it since the country's second generation leadership.

Moreover, letters and congratulatory messages Kim Jong Un sent to domestic people and foreign leaders still occupied the headlines in the country during this period of time. Therefore, while international media was speculating about the "grave illness" of the DPRK leader, everything was business as usual for ordinary people in the country. Actually, Kim Jong Un's so-called disappearance also lasted shorter than his father's longest one - 51 days in 2008.

For the above reasons, many observers on the Korean Peninsula pay more attention to the shifting role of Kim Yo Jong, who regularly attends ribbon-cutting ceremonies as her brother's top assistant.

Since the DPRK's diplomatic breakthrough in 2018, Kim Yo Jong always stood alongside her brother, the top leader of the DPRK, and handed him a pen during many public events. This time she sat on the stage, right next to Kim on Friday's Labor Day celebration, along with the DPRK's cabinet premier and other leaders of the ruling party and government.

That change again confirms the prediction by some analysts that Kim Jong Un is reinforcing the ruling elite circle of "bloodline of Paektu" and Kim Yo Jong has increasingly been seen as a key figure since she was elected as an alternate member of Politburo in April.

The official media of the DPRK has increased reports about the "bloodline of Paektu" since October last year in order to emphasize the legitimacy of Kim Jong Un which, according to some analysts, also explained to some extent why Kim Yo Jong's role is shifting.

Kim Jong Un, as the DPRK's legitimate successor, mounted twice in 2019 the top of the Mountain Paektu, where his father was born, riding white horse. During his later trips, the country's reporters were the first group of visitors allowed to visit the site. And since last December, nearly 56,000 cadres, workers, soldiers and students have visited the mountain.

Kim Yo Jong was one of Kim's company when they rode white horses standing at the crest last October. What is more interesting is that, according to the photos released by the state media, the two horses they rode on marched in tandem. Her horse was not as white as her brother's, but it is worth noting that her silver riding accessories were different from all other officials'.

And since June 2019, Kim Yo Jong has regularly been on the accompanying list of Kim according to the state-run media like the KCNA and Korean Central Television. During the governmental media reports when Chinese President Xi visited the DPRK last June, Kim Yo Jong was officially ranked as one of the "leadership comrades of the party and government."

All the changes indicate that Kim Yo Jong is playing a more important role in the ruling power framework of the DPRK and she would contribute more to the country's  policy-making of internal and external affairs, as the core figure of the elite group in the nation.

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