President Donald Trump recounted an absolutely astounding detail about one of his conversations with Chinese President Xi Jinping in comments published by the Wall Street Journal on Wednesday afternoon. Apparently, Trump came into his first meeting with the Chinese leader, in early April, convinced that China could simply eliminate the threat posed by North Korea’s nuclear program. Xi then patiently explained Chinese-Korean history to Trump — who then promptly changed his mind.

“After listening for 10 minutes, I realized it’s not so easy,” the president told the Journal. “I felt pretty strongly that they had a tremendous power [over] North Korea. ... But it’s not what you would think.”

Four quick observations about this:

Trump thought China could fix North Korea until the Chinese president politely informed him that North Korea is in fact complicated. Trump seems to have required the leader of China to explain basic facts to him that he could have Googled, or at least asked one of the many US government North Korea experts about. Trump came to a profound realization about one of the most dangerous conflicts on earth after a 10-minute conversation. Trump is getting his information about East Asian affairs from the leader of America’s largest rival in the region.

Around the same time the Journal piece was published, North Korea informed reporters to prepare for a “big and important event.” Initial reports suggest that Pyongyang is planning to test a nuclear device for just the sixth time in the country’s history. There’s no word yet on how the Trump administration plans to respond.