Japan cracks down on rebel pupils who refuse to sing
Tokyo's education authorities have ordered head teachers to make sure students stand to attention and sing the national anthem. The move follows a rash of protests by students and teachers since Japan made standing for the anthem compulsory in 1999 in an attempt to encourage patriotism.
Ref. https://news.independent.co.uk/world/asia/article351538.ece
I believe a measure of respect must be shown for one's country, however, I do not believe one should be forced to sing. Often, the words of Anthem may have political statements that are not agreeable, but I do believe one can stand at least as a show of patriotism / respect, just not forced to sing.