"More than 300,000 workers throughout Germany took to the streets today in an escalating showdown between unions determined to protect postwar gains and employers eager to halt a deepening recession.</br></br>Ten days into eastern Germany's first strike in more than half a century, workers in three states in the formerly communist east voted overwhelmingly to join the job action, while western German workers staged demonstrations and brief walkouts in sympathy.</br></br>About 40,000 metalworkers and workers in related industries in the eastern part of the country have joined the stoppages.</br></br>The strike started May 3 after employers unilaterally canceled a two-year-old contract that promised eastern workers a 26 percent pay raise this spring and parity with western wages by 1994. The strike - a potentially fatal blow to many eastern firms that have been unable to compete in the new western economy - is a watershed in German labor relations, a level of confrontation not seen since the 1920s.</br></br>""In 1928, we suffered the same conditions as now,"" Manfred Foede, a leader of IG Metall, Germany's largest union, told a rally here today. ""Mass unemployment, a trend toward right-wing radicalism and broken union contracts. The unions did not protect themselves enough then, and we all know what happened. This time, we will protect ourselves."""