Obama meets Japanese Emperor Akihito at Imperial Palace

President Barack Obama has visited Tokyo's Imperial Palace, where he was greeted by Emperor Akihito.

The visit is part of an official tour of Japan, aimed at reinforcing the importance the US places on Asia.

Although diplomatic issues are high on his agenda, Mr Obama is also under pressure to perfect his Japanese etiquette.

According to the BBC's Mariko Oi, the president was criticised for "bowing too deeply" when he toured Japan in 2009.