Updated

Japanese officials are wary ahead of the arrival of outspoken Philippine President Rodrigo Duterte. Their concern is not only about his foreign policy toward the U.S., but also about his informal style. They are paranoid about him chewing gum in front of the Emperor.

Duterte arrives in Tokyo later Tuesday for a three-day visit, his first as Philippine leader and as his recent remarks on foreign policy and freewheeling style have captured national attention here.

For diplomats and political leaders, the main issue is Duterte's foreign policy toward Washington and how Japan can help mend their ties, but they are also worked about his manners. In a country where formality and politeness are highly valued, just about everything Duterte stands out.