Oakland public school teachers went on strike Thursday, but authorities promised to keep schools open for the district's 50,000 students by using administrators and substitutes.
The 3,500-member Oakland Education Assn. has been working without a contract for more than a year. Class size, salaries and the early retirement program have been key sticking points.
"When it comes to the education of our children, we've all received a failing grade," said picket Louella Harris. "We've got to do a better job."
District spokeswoman Sherri Willis blamed the union; the strike followed a week of sluggish talks.
"They left. They didn't declare an impasse. They just said there's not enough progress . . . even though they were the ones who called for around-the-clock negotiations," Willis said.
Both sides agreed to a mediator's request to meet again Saturday.