The Tokyo Metropolitan board of education punished 52 public school teachers Thursday for refusing to stand up and sing the "Kimigayo" national anthem at March graduation ceremonies.

The penalties ranged from warnings to pay cuts -- depending on how many times the teachers disobeyed orders from school principals to rise and sing the anthem.

The board issued a notice in October 2003 to principals of metropolitan government-run schools, telling them to order all teachers to stand and sing the anthem at graduation and entrance ceremonies.