

Because advancing to the next Age locks all researchers of the former one.

But you should think wisely and pick your researchers.

The good thing is that you have a lot of researchable techs to spend on. Mostly due to their heavy requirements of Landmarks and the Grenadier units, which is itself a very powerful unit. Hence you will find yourself often falling short. Although they can mine for Gold faster and has the ability to earn passively, most of the time it is not enough. To advance to the next Age, you need to build two Landmarks which means a hefty requirement of resources and time. Everything for The Chinese is dependant on spending Gold and other resources, but mainly the former. For most players, it becomes more work than fun. The Chinese are an extremely difficult Civilization to play with. Moreover, their landmarks also give huge bonuses that help you in battle, gold, and resources. Relics can be used to boost all different stats such as an attack, defense, range, etc of all units.
