I agree that map in china should be more detailed.
Japan Army always concentrate their limited land force and attck a single point on CHI defence line, once pierced through, the whole defence line crashed. i.e 10 JAP divisions trying to attack a defence line defended by 100 CHI divisions. what will happen if the line is made up of 4 provinces (I mean "regions")? 25 division per region. hard for 10 JAP divisions to break through. However, what will happen if the line is made up of 20 provinces? (Due to CHI officers training for only "WWI single line" defence tactic, and
CHI army's low morale, one point is pierced through, the whole line is collapsed).
A defence line made up of 3-4 regions(provinces) and of 15-20 regions with the ssame land force (i.e. 100 divisions), which one is more easier to be broken through?
That is why Japan "travelled" deep into inner China in 1937-1938 in HISTORY but receive a failure in 1937-1938 in HOI2DA1.2.