Until a Bill was enacted in August this year, Japan’s de facto national flag, the Hinomaru - the familiar red sun on a white background - and “Kimigayo” anthem had no legal status. Many schools, particularly in the Hiroshima area, excluded them from school ceremonies.

The law was brought in after a Hiroshima high school principal, Toshihiro Ishikawa, committed suicide this spring after being caught between the state’s instructions to sing the song and the school’s opposition to it.

Shortly after his death the Hiroshima board of education issued an unprecedented order from the education ministry to its high schools ordering the anthem to be sung at school ceremonies.

Following the order the number of schools honouring the national symbols at opening ceremonies in September in Hiroshima shot up to 87 per cent from 12 per cent. The schools which are still refusing to raise the flag and sing the anthem are now being quizzed by the police who haven’t said what action they will take if they do not comply with the new law.

National symbols are a sensitive issue in Japan where they are seen as reminders of the country’s imperial and militaristic past. “The police action has infringed the freedom of thought and belief which is guaranteed by Japan’s Constitution,” said Shinji Fujikawa of the Hiroshima Teachers’ Union.

“The Japanese police used to strictly observe and control people’s speech and writing before World War II. Now, it seems it is no different. Under these circumstances, we will make every effort to defend freedom of thought, belief, speech and writing.”