So now we know that North Korean leader Kim Jong-un and his wife were indeed onboard that special reinforced train seen traveling from the North to Beijing this week.
They are now back in Pyongyang after wrapping up his short stay in the Chinese capital.
While we await more information,... experts are paying attention to the timing of the visit.
Lee Seung-jae reports.
The highly secretive visit by the North Korean leader to China may indicate the regime's need for support from its closest ally ahead of Kim Jong-un's upcoming summits with the presidents of South Korea and the U.S.
Prior to the confirmation of Kim's trip to Beijing,... observers had already been saying it would be highly unusual for him to meet with U.S. President Donald Trump without seeing Chinese President Xi Jinping first,... given the importance of Pyongyang's ties to Beijing.
Pundits have some ideas about the reasons for Kim's visit,... including the need to shore up ties which have become strained due to the regime's repeated nuclear and missile tests.
Also,... with increasing signs that sanctions imposed on the North have begun to hurt the isolated state,... experts say Kim may have realized that he cannot survive the economic squeeze.
They say Kim may be seeking an easing of sanctions as a concession for continuing dialogue as China has been less willing than the U.S. to punish the North as long as it commits to diplomacy.
And as Xia Yafeng, a historian at Long Island University puts it,... Kim's playing one superpower against another.
With claims the North has nuclear missiles capable of hitting the U.S. mainland,... the young North Korean leader appears to be focused on rebuilding the nation's economy.
In order to do that and prevent his regime collapsing,... experts say he will need the help of China and its vast economy.
Lee Seung-jae, Arirang News.