The South Korean Foreign Ministry also expressed regret over Tokyo's decision.

"It is very regrettable that the ministry approved the textbook publishers' recent applications for the removal or change of related expressions," the ministry said. It stressed that the forced nature of the mobilization, recruitment and transfer of the military "comfort women" is an "undeniable fact" backed by victims' firsthand accounts, and Tokyo itself has already acknowledged its past misconduct.

In 2015, at a session of UNESCO's World Heritage Committee, the Japanese government admitted that forced labor victims were brought "against their will and forced to work under harsh conditions".

Takakage Fujita, director-general of a civil group dedicated to upholding and developing the 1955 Murayama Statement, said the "comfort women" issue is a huge crime by the Japanese military government, and "many victims and their relatives are still bleeding today".

The Murayama Statement, released by former Japanese prime minister Tomiichi Murayama, advocates historical recognition and reconciliation with Asian countries by Japan.

To commemorate the September 18 Incident, Fujita's group organized a rally in Tokyo on Friday, which was attended by about 200 people. Fujita hopes the event will urge the Japanese government to learn lessons from history and improve relations with China.

"The top leader of Japan should have a correct view of history, reflect on the past, and look forward to a peaceful future," Fujita said.

"Civil groups all over the world are building 'comfort women' statues and memorials to remind people of this dark history and to make sure that it will never be forgotten," he said, adding that all peace-loving people should remain alert to attempts to whitewash this part of history.