Supported by parents and students, teachers in the central state of Hesse stormed the city square in front of the administrative headquarters in Frankfurt to demonstrate over plans by the regional government to prolong their working day by one hour - without pay - from next year.
According to the teachers' union, GEW, 76 per cent of teachers balloted voted in favour of further one-day lightning strikes.
Meanwhile, there has been an 11 per cent increase in the number of school-leavers in Germany who are without training places, according to the latest figures released by the employment department.
More than 300,000 youngsters cannot find places but, it was reported, compared with last year, there are also 15.2 per cent more unfilled training vacancies.
The new figures came a day before the Chancellor, Helmut Kohl, met regional education ministers to discuss cutting school days for trainees.
The government proposes to reduce schooling from two days a week to one in the second and third year of training programmes.