Yangko drama, or Yangko opera (秧歌剧 pinyin Yangge-ju), is a form of Chinese sung theatre. An example is the founding piece of the China National Opera when it was founded in Yan'an in 1942, which was with a performance of a Yangko drama Brothers and Sisters Opening up the Wasteland (《兄妹开荒》). The Yangko owed something to normal huaju spoken drama, but with dance, and songs added.
References
Yangko Wikipedia(Text) CC BY-SA