Twenty-five teachers working at schools operated by the Tokyo Metropolitan Government filed a lawsuit Thursday demanding that the metro board of education nullify the reprimands they received for refusing to stand and sing "Kimigayo" at school ceremonies this past spring.

In a complaint lodged at the Tokyo District Court, the teachers also demanded damages in lieu of pay cuts they suffered for failing to stand when the national anthem was played during graduation and entrance ceremonies.

The teachers were ordered by the board of education to participate in "training programs" after disobeying its order that all teachers stand and sing the anthem during school ceremonies.

The teachers said their personal rights were violated by this order, given that the programs in question deemed the teachers' conduct based on ideology and belief as being "delinquent."

Last year, teachers at metro government-run schools sought nullification of similar reprimands they received in connection with the national anthem, but the Tokyo District Court rejected these requests.

"Kimigayo," unofficially translated in English as "his majesty's reign," was defined under law as Japan's national anthem in 1999, but its status remains a contentious issue.