You are right. No matter which dynasty or generation, the emperor has only one wife, and that is the queen. Other levels of concubines, however favored, are just concubines, just different levels. In other words, the emperor practiced polygamy, which was strictly stipulated by the patriarchal clan system. In fact, this is an inheritance and protection system. After the death or abolition of his wife, the emperor can re-elect the queen, but only one.

According to the palace history of the Zhou Dynasty, the emperor's first wife was a queen, and only one person was allowed to preside over the affairs of the inner palace. The second is the princess, including one imperial concubine, two concubines and four concubines. The third place is six people. The queen is in the middle palace and the concubines live in the twelfth house. The fourth is a noble person, the fifth is forever, and the sixth is a promise. This is not limited to the amount, but depends on the energy and love of the emperor.