The trial has begun in China of 14 people accused of organising a sex party for hundreds of Japanese tourists on a sensitive wartime anniversary.
Two of the hotel's employees are among the defendants
The incident in the southern city of Zhuhai in September prompted an official Chinese complaint to Japan.
About 400 Japanese men and 500 Chinese women were reportedly involved in the three-day orgy at a hotel.
It ended on the eve of the anniversary of the Japanese attack on China's north-east in 1931.
This marked the beginning of Japan's brutal occupation of the country.
A BBC correspondent in China, Francis Markus, says the case is loaded with diplomatic sensitivity and emotional charge and reinforces a historic bitterness between the two countries
All of the defendants are Chinese and charged with organising prostitution.
They reportedly include 12 pimps and two employees of the Zhuhai International Conference Centre Hotel.
A prosecutor's office official said he was unaware of any plans to press charges against any Japanese citizens.
Security at the Zhuhai courthouse was tight and a court
official refused to allow reporters in.
A notice from the court published in the Beijing Times
newspaper said the proceeding was closed to the public
because it involved matters of "personal privacy".
Prostitution, although illegal, is common in China and is
often practised openly in tourist hotels in major cities.
But the timing of the event in Zhuhai prompted outrage in China, where many feel
that Japan has failed to atone for its wartime brutality.
Many of the Japanese involved were said to be employees of a Japanese construction company that sponsored their trip.
Japan's foreign ministry said the company acknowledged
paying for "companions" at a reception, but denied
sponsoring an orgy.