When Xi Jinping makes his first visit to North Korea as China's president on Thursday, he'll be broadcasting a message to the U.S. and Japan: When it comes to Pyongyang's nukes, Beijing still wields immense power.

With the Group of 20 summit in Osaka just over a week away, Xi's two-day state visit for talks with North Korean leader Kim Jong Un appears timed to deliver this message to its intended target, experts say. The trip could rocket the denuclearization issue to near the top of the agenda for expected bilateral talks between Xi and U.S. President Donald Trump and Prime Minister Shinzo Abe on the sidelines of the June 28-29 summit.

"I think the message is simple: China is the key player in Northeast Asian affairs," said Zhiqun Zhu, a political science professor at Bucknell University in Pennsylvania. "Without China's assistance, the stalled North Korea nuclear negotiations will not go anywhere."