The 37-year-old man, identified by his family name Liu, hurled four petrol bombs at the embassy building in central Seoul on Sunday morning, scorching an outer part of the wall, a Seoul police officer said.
There were no reports of injuries.
Police were questioning Liu, a resident of the southern Chinese city of Guangzhou, who entered the country on a tourist visa via Japan late last month, to determine the reasons behind the attack, the officer said.
The Yonhap news agency said the man had told investigators that his grandmother had served as a "comfort woman" for Japanese troops and that he had staged the attack in protest against Japan's wartime atrocities.
Historians say hundreds of thousands of women from Asian countries, mostly Koreans and Chinese, were forced to work at front-line brothels for the Japanese military. The Korean peninsula was under Japanese colonial rule from 1910 to 1945.
Tokyo has apologized for its treatment of the women but refused to hold talks on compensating the ageing victims.
(Reporting by Sung-won Shim; Editing by Ron Popeski)
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