In the run-up to the spring graduation ceremonies, authorities, teachers and pupils are braced for more conflict over flying Japan’s national flag and singing its anthem in school events.

Tokyo’s board of education has issued a new order to heads of metropolitan, government-run junior and senior high schools to ensure that teachers “appropriately” instruct students to show respect for the Hinomaru flag - the familiar red sun on a white background - and sing the Kimigayo anthem during school ceremonies.

The education board is planning to send large numbers of observers into schools to make sure that the flags are flying and the national anthem is sung to the satisfaction of the most ardent patriot.

Of Japan’s 47 prefectures, Tokyo is by far the strictest about singing the national anthem at public school events, which was made compulsory nationally in 1999.

Shintaro Ishihara, the city’s far-right governor, has said this year that he will not tolerate rebellion from pupils or teachers.

Rather than face discipline or a showdown over what some teachers regard as either a matter of conscience or a violation of Japan’s constitution, many teachers will report in sick on school ceremony days.

Since 1999, more than 1,000 teachers have been punished, admonished or had their salaries docked for not standing, singing or failing to meet the requirements set down by the district.

Some teachers have been sent to “re-education” classes.

Many staff have appealed, but the Japanese courts have upheld all punishments meted out by local authorities to rebel teachers.

In 1999, one school principal committed suicide after finding himself unable to resolve an issue over singing the Kimigayo during a graduation.

The re-introduction of these practices is affecting teacher recruitment, according to Michio Nitta, professor of education at Tokyo university.

He said: “Generally speaking, those teachers who resist coercion are left-of-centre but are good teachers, so Tokyo may be losing good teachers because of Ishihara’s emotional politics.

“These rightist politicians are shooting themselves in the foot.

“This kind of outright coercion is damaging the real moral support to the national anthem and flag.”

Feelings continue to run high over the use of what for many teachers are still potent symbols of the country’s militaristic past, and which are now a growing cause cel bre for a newly emboldened, right-leaning government.