But note here that Xichuan refers to Chengdu and Sichuan, while Dongchuan is definitely not Yunnan or Chongqing, but a place that includes Hanzhong, a military stronghold.
Surprisingly, it belonged to Ada and was later transferred to Liu Zhang, while Dongchuan belonged to Zhang Lu and was later occupied by Cao Cao. Erchuan is collectively called Yizhou.