South Korean President Moon Jae-in has less than one year to finish up his North Korea agenda before the next presidential elections start. Most urgently, he has a very tight window to revive U.S.-North Korea talks before he hands the fate of nearly all of his diplomatic efforts to a new successor.

That approaching high-pressure deadline is exactly why Moon has recently started to change his attitude towards Japan. It's widely known that the new U.S. president, Joe Biden, takes the alliance system very seriously and therefore worries about the deterioration of the relationship between Seoul and Tokyo.