Philippines President Rodrigo Duterte is set to visit Japan but will not meet the country's emperor amid conjecture that the Japanese monarch might be embarrassed by the leader, who has little regard for diplomatic protocols. Duterte will visit Japan by the end of October to boost bilateral cooperation and discuss regional security.

Duterte will be among the first leaders to meet Japan's Prime Minister Shinzo Abe after his recent re-election. Though Duterte's visit was confirmed by Japan's Cabinet Secretary Yoshihide Suga during a press conference on Wednesday, 25 October, it is yet to be formally acknowledged by officials from the Philippines side.

In his meetings with the Japanese premier, Duterte is set to discuss some of the compelling issues in the region, including the threats from North Korea. "[Japan] hopes to deepen cooperation with the Philippines as strategic partners to contribute to the region's stability and prosperity," Suga added.

Curiously, Suga did not explain exactly why the visiting president will not meet Emperor Akihito. When Duterte visited Japan in 2016, he could not meet the monarch since the royal's uncle had died at the time.

"They are paranoid about him chewing gum in front of the emperor," an unidentified Japanese official was quoted as telling the Associated Press during the preparations for Duterte's 2016 visit. However, the tough-talking leader, who has raised eyebrows with his devil-may-care attitude, was scheduled to meet the emperor at the time but eventually couldn't.

In the past, Duterte has been seen chewing gum during a meeting with Chinese President Xi Jinping. He was also seen with his shirt sleeves rolled up while meeting Cambodian King Norodom Sihamoni in 2016, which caused an uproar in Cambodia.

Japan is one of the most protocol-conscious countries in the world and Emperor Akihito is considered as a revered figure in the nation.