The main hall at Shuri Castle in Okinawa was burnt to a skeleton, with firefighters spending hours trying to bring the blaze under control.
A popular tourist attraction, Shuri was built more than 500 years ago as the royal castle of the Ryukyu Kingdom. The castle was largely restored in 1992 as a national park and was designated as the UNESCO World Heritage site in 2000.
The fire was brought under control by early afternoon, a local fire department spokesman said, adding that the blaze had consumed more than 4,800 square metres of the castle complex.
“All the three main buildings have burnt down, with nothing left behind,” said Daisuke Furugen, an official with the Naha fire department.
On the scene, a local fire spokesman said the blaze had proved extremely difficult to control.
“The radiant heat was very strong. Firefighters had serious difficulty approaching it,” he said in comments shown on national broadcaster NHK.
It was not yet clear what caused the blaze, which was reported to authorities around 2:40 am Oct 31st. There were no reports of injuries.