Seeking to be seen as a viable leader, so as to seek food and oil in the future.
Given his age, I feel its possible he could trigger something which could then escalate in a very sensitive area.
China and Russia are now peaceful but not Pro USA
China and Japan are enemies
Japan and USA are friends
Japan and PRNK are enemies
Delicate to say the least, but like the Cold War, all participants above are reasonable and mature people, apart from Kim Jong Un