German women won the voting right highlighted by Germany's 1914 Women's Day in 1918.
Germany's 1914 observance was held on 8 March and strongly emphasized women's suffrage. At the time, women could campaign for political rights but could not vote in national elections. The breakthrough came during the political revolution that ended the German Empire at the close of World War I.
On 12 November 1918, the Council of People's Deputies proclaimed equal, secret, direct and universal suffrage for men and women aged 20 or older. An electoral regulation issued later that month put the change into law. The Weimar Constitution of 1919 then gave women's suffrage constitutional standing.
The year 1919 is a tempting alternative because German women first exercised the new right in the election for the Weimar National Assembly on 19 January 1919. The question asks when they won the right, however, so 1918 is the canonical answer; 1919 marks its first nationwide use at the polls.