Just as I was appearing live on TV Saturday morning, the world learned that U.S. President Donald Trump had tweeted: "After some very important meetings, including my meeting with President Xi of China, I will be leaving Japan for South Korea (with President Moon). While there, if Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!" As a former diplomat, it was an extremely uncomfortable moment for me.

The reason was simple. I was so stunned and then dubious about the uncanny tweet that I became speechless for a moment in the middle of a Saturday morning news show. In the program, we were reviewing the Group of 20 summit in Osaka but, even at the end of the show, I could not imagine that a Trump-Kim handshake would ever take place.

No matter how impulsive and intuitive Trump might have been, it was the first visit by a sitting president of the United States into the North Korean side of the Demilitarized Zone. I don't challenge its historic importance. I wonder, however, if this third but potentially only symbolic U.S.-North Korea summit should eclipse the significance of the Osaka G20 summit.