On 27 February 2007, the Supreme Court of Japan dismissed the appeal from an elementary school teacher who had been reprimanded for having refused to play the piano at her school's entrance ceremony for singing the national anthem in unison. The teacher had argued that the disciplinary measure were illegal.
When the Law on the National Flag and the National Anthem was adopted in 1999, the then Prime Minister and other ministers concerned explained that the legislation would not make it mandatory to hoist the national flag and to sing the national anthem at school ceremonies and other opportunities; their treatment at school were not to be changed. Nevertheless, a series of lawsuits have been filed since then against forcing students and teachers to sing the national anthem in unison, which is allegedly in violation of freedom of thought and conscience.
The music teacher in this case, who had refused the principal's order to play the piano, argued that she could not sing or accompany to the national anthem Kimigayo, because it had been associated with Japan's aggression against Asia during the former half of the 20th century. She invoked the right to freedom of thought and conscience, which is protected under Article 19 of the Constitution of Japan.
The Supreme Court found that the act of singing the national anthem in unison and playing the piano for that purpose is generally not associated with someone's views on history or the world; thus an order to play the piano for the national anthem cannot be regarded as negating such views. Such an order to a music teacher is also within reasonable possibility, not constituting imposition or prohibition of a particular ideology; moreover, the order is not unreasonable in accordance with the School Education Law and other relevant regulations. On the basis of this reasoning, the Supreme Court concluded that the order to play the piano for the national anthem is not incompatible with Article 19 of the Constitution.
Source: Judgment of the Supreme Court