A tricky one: Economic Reserve, Prussian war

In Economic reserve the generals play a lesser role, altho good generals avoid you the cost of investing in more troops and you can focus on expanding cities and save money. Important are the "Princesses". If you have Kathrine and Sakurako, boost your knowledge and cut your upgrade costs. 

If you upgrade your cities up to "4" and expand all buildings to max you will do it. Don't rush destroying the enemies as they will regen. If you are left with 1-2 enemy units, dont fight them

Here is the Video Guide