A Japanese public high school has come under fire for its strict policy regarding the color of its students’ hair.

An 18-year-old teen filed a lawsuit in late October seeking ¥2.2 million ($19,000) in damages from the Osaka prefectural government, claiming that her school had ordered her to dye her naturally brown hair black if she wished to continue attending classes.

The young woman’s mother had informed Kaifukan High School before the teen started attending that her hair was naturally brown, but teachers ordered the student to dye it black, according to documents the plaintiff submitted in court.

The student developed a rash and scalp irritation after dyeing her hair repeatedly but her teachers continued telling her that her hair was not black enough, demanding that she comply or leave the school, the petition said.

During one conversation with her mother, the school said it would even demand that blond foreign students dye their hair black because that was the rule, the petition said. The school also has a policy that prohibits students from dyeing their hair.

The school’s decision sparked criticism online, with supporters of the student’s lawsuit describing their own experiences of being forced to conform to the status quo.

Sayaka Akimoto, a former AKB48 member who is Filipino-Japanese and who does not have naturally black hair, admitted in a post on Twitter that she had also dyed her hair black at high school after she was accused of dyeing her hair. Akimoto’s father defended his daughter, telling the school that its policy was ridiculous.

“Rules are important,” she wrote, “but there must be many other things that are more important.”

The post has since received more than 21,000 “likes.”

Users of social media have argued the issue is important in light of the wider context. With more and more people in high school coming from diverse backgrounds, strict rules regulating the natural appearance of students could be perceived as discrimination.

Twitter user @mi_adhd described her own experiences at school in response to Huffington Post Japan’s coverage of the Osaka story.

“I was originally a brunette, so my mother submitted an ‘irregular dress code’ form when I entered middle school,” the post read. “The school’s insistence that everyone must be the same was one of the reasons I was bullied for being different. We’re not living in ancient times. Even with all this talk of diversity, if the current state of education is like this, there’s no way it will work.”

Twitter user @jaco_hideaki agreed.

“I saw this mentioned elsewhere, but if you consider hair color and skin color to be natural physical characteristics, this is a serious human rights violation,” the post said. “If we’re striving to create a diverse community that accepts all individuals, including people who identify as LGBT, we should acknowledge these aspects as well.”

Supporters of the high school argued that media coverage of the school’s policies was biased. One Twitter user claiming to be a graduate of Kaifukan High School started an account specifically to rebuff the allegations, refusing to believe that their alma mater would treat a student in such a manner.

A former elementary school teacher posted a similar statement, arguing that the school should be given an opportunity to present its side of the story.

The Osaka prefectural government, which runs Kaifukan High School, has asked the court to throw out the lawsuit.

Judging by the public’s online reaction, however, the teenager’s recent experience is not an isolated incident and debate over the country’s outdated ideas on conformity look set to continue.