During the Anti-Japanese War, Hebei people came to Inner Mongolia from Zhangjiakou. Who knows this history? My grandfather came to Inner Mongolia from Dingzhou, Hebei.

It seems that Feng Yuxiang and Ji Hongchang led troops from Zhangjiakou, then the capital of Chahar (including today's Zhangjiakou, Datong and Baotou) to Duolun, Inner Mongolia. In fact, there seems to be a book about this history. I have seen it before, but now I can't remember the name.