The city on horseback is not Jinan, but Erdos. Jinan is not a city on horseback. Jinan is located in the west of Shandong Province, with developed transportation. There is no such thing as using horses as a means of transportation. Moreover, there are almost no horses in the countryside of Jinan, and there is no so-called city on horseback.
Horse is a kind of domestic animal, and people keep horses mainly for riding. If there are many people who often ride horses in a city, the city will be called a city on horseback.