Generally speaking, Tongrentang and Beijing Tongrentang are the same company. Tongrentang is a trademark, its owner is Beijing Tongrentang, and its full name is China Beijing Tongrentang (Group) Co., Ltd.
However, due to the special experiences of Tongrentang in history such as four-room splitting and public-private partnership, as well as some historical cooperative relationships, we can now see some corporate names with "Tongrentang" in them, such as Nanjing Tongrentang, Tianjin Tongrentang, and Chengdu Tongrentang, etc., but they are only used as corporate names and do not have the ownership of the trademark name of "Tongrentang".