Eth­nic Mon­go­lian stu­dents and par­ents in north­ern Chi­na have staged mass school boy­cotts over a new cur­ricu­lum that would scale back edu­ca­tion in their moth­er tongue, in a rare and high­ly vis­i­ble protest against the rul­ing Com­mu­nist Party’s inten­si­fied push for eth­nic assimilation.