Britain's King Charles III welcomes the visiting Japanese emperor and empress

LONDON (AP) — King Charles III welcomed the Japanese emperor and empress for a state visit that began on Tuesday, offering the best in pomp and circumstance as the U.K. seeks to bolster its role as the most influential European nation in the Indo-Pacific region.

Emperor Naruhito and Empress of Masako are to attend a banquet hosted by the king, lay a wreath at Westminster Abbey and tour one of Britain’s premier biomedical research institutes. But the emperor began this week’s trip by visiting a site that has special meaning: The Thames Barrier.

The retractable flood control gates on the River Thames seemed a natural destination for a royal long interested in the waterway that runs through the heart of London. Naruhito studied 18th-century commerce on the river as a graduate student at the University of Oxford some 40 years ago.

He chronicled the interest in his memoir “The Thames and I,” together with his fondness for Britain and its people. The future emperor got a chance to experience life outside the palace walls, including doing his own ironing, going to the bank and taking part in pub crawls.

Tuesday's ceremonial welcome seemed warm. Charles and Naruhito, who have known each other for years, settled into the back of a carriage and chatted like old chums.

Masako wore a mask in her carriage because of a horse hair allergy.

Both countries look to each other as a source of stability and mutual reassurance at a time of potentially destabilizing global political change.

“We’ve had a long history of engagement,'' said John Nilsson-Wright, the head of the Japan and Koreas program at the Centre for Geopolitics at the University of Cambridge. “But ... this current visit (is) a reflection of both the personal ties of affection between the two royal families (and) perhaps most importantly of all, the geopolitical significance of the relationship.”