Prime Minister Shinzo Abe has long boasted about his diplomatic skills, but in just two weeks he has suffered several humiliating setbacks, raising questions about his claimed prowess.

The latest crisis emerged on Wednesday in the Upper House when Abe admitted that the diplomats and intelligence officials failed to get advance knowledge of North Korean leader Kim Jong Un's surprise trip to Beijing for his first summit with Chinese President Xi Jinping. The summit was confirmed earlier that day.

Abe said he learned of the Kim-Xi summit "via news reports." This stood in sharp contrast with Washington and Seoul, which reportedly received advance notice from Beijing.