Emperor Naruhito, Empress Masako and their only child Princess Aiko visited Okinawa Prefecture for an overnight stay.

They arrived at Naha Airport on June 4 to begin their tour of places that commemorate the Battle of Okinawa, which involved fierce fighting that lasted from April to June 1945 on the southwestern Japanese island prefecture.

It is one of the few places in Japan where ground battle took place during the Pacific War.

The imperial family visited the National War Dead Peace Mausoleum in the city of Itoman.

There they offered flowers and bowed in front of a hall where the remains of some of the people who died in the Battle of Okinawa are kept.

This year marks the 80th anniversary of the end of World War Two.

The emperor and his family spoke with survivors of the Battle of Okinawa and bereaved relatives of those who died in the fighting. 

More than 180,000 soldiers and civilians combined perished in the battle.

Okinawa was under US rule from 1945 to May 1972 when it was reverted to Japan.

The three also stopped at the Cornerstone of Peace where the names of the war dead are inscribed on stone walls.

They listened to explanations in front of a wall where the names of 342 people were newly added in May.

While the emperor and empress have been to Okinawa multiple times, this is the first time for Aiko to travel to the prefecture.

On the second day of their stay, the imperial family headed to a place that memorializes victims of the sinking of the Tsushima Maru, a ship that was carrying students evacuating from Okinawa to other parts of Japan in 1944.

The ship sank after a torpedo attack by the US military during the Pacific War, killing 1,484 people, including 784 children.

The emperor, empress and princess offered flowers at a cenotaph built in Naha in memory of the victims.

This is the first time for all three to visit this location.

The family then entered the Tsushima Maru Memorial Museum.

The facility was established in 2004 to inform future generations about the Tsushima Maru incident and teach people about peace and the value of life.

The victims' belongings and photos of the deceased are displayed at the museum.

An aide said the emperor and empress had heard stories about Tsushima Maru from their parents Emperor Emeritus Akihito and Empress Emerita Michiko, who visited the museum and cenotaph in 2014.