North Korea has concluded one of its biggest leadership shakeups in years. While understanding leadership dynamics in Pyongyang is akin to reading tea leaves, it is clear that the shuffle has consolidated the power and status of Kim Jong Un, already the country's supreme leader. As ever, all decisions are made by him and dealing with Kim is the only way to deal with North Korea on the state-to-state, or diplomatic, level. This has implications for Japanese diplomacy: Kim is the only interlocutor that matters and Prime Minister Shinzo Abe will have to deal with him directly if there is to be any progress in the bilateral relationship.

Last week, the Supreme People's Assembly of North Korea, the country's rubber-stamp parliament, approved the selection of Choe Ryong Hae as president of the Presidium of the Supreme People's Assembly. Choe replaced Kim Yong Nam, 91, who had served in that position since it was created in 1998. The president is the de facto head of state, who meets foreign guests and convenes sessions of the Supreme People's Assembly. Choe was also elected first vice chairman of the State Affairs Commission, a new post, which effectively establishes him as the second-ranking official in the government hierarchy. North Korea watchers have charted Choe's rise since Kim took power in 2011, and Choe is thought to be one of Kim's confidantes. At one point in 2015, however, he was reported to have fallen from grace and was thought to have been sent to the countryside for re-education, but he has apparently been rehabilitated — a reminder that there are second chances even in Kim's leadership.

In addition, Kim Jae Ryong, who served as a party leader in Jagang Province, was named premier, replacing Pak Pong Ju, who had been premier since 2013. Little is known about Kim, but Pak implemented a reform program that created more room for market forces. He was promoted to vice chairman of the ruling party, so it is likely that his reforms will continue.