Germany is a beast and probably the strongest nation in Hearts of Iron IV. It has huge manpower, industry, technology, and many tanks. So, is defending against Germany possible in HOI4? The answer is yes, of course it is possible and I will guide you through that.
HOI4 defending against Germany requires different approaches depending on the country you are playing. But the key is, patience and correct preparation.
HOI4 Defending France
This is a tough one but not impossible. There are couple of key points that allows France to defend against German Reich. Let us begin.
All your divisions must have engineer company for the maximum entrenchment and defensive bonuses.
Defensive focus must have taken in order to unlock army defense advisor Maxime Weygand. (Division defense +10%.)
Other important focuses are:
Encourage Immigration: Removes full employment. (Recruitable population factor -25%.)
General Work Council: Remove inefficient economy. (Factory output -20%, and dockyard output -20%.)
Defensive Stratagems: Remove disjoint government. (Daily political power cost +0.80, stability -10%, and surrender limit -50%.)
Army Reform: Remove victors of the great war. (Recruitable population -0.30%, war support -5.00%, and land doctrine cost +50%.)
You need to defend three frontlines against Germany. African border is a liability and not that really important.
Once USA joins the war and German Reich attacks Soviet Union you can start testing and pushing frontlines. Before that, I wouldn’t try to push through my forts. Pushing against Germany when you are not ready ends up in losing controlled forts. And eventually capitulation.
1. Maginot Line
France’s main border against Germany is Maginot line. Entire line have maximum level land forts. Therefore it is almost impossible to breach.
Simply put 15-20 fully equipped divisions on the Maginot line. Germany can not push through. Of course that is why German Reich attacks Benelux countries to open another frontline. But worry not, we will prepare for that before hand.
2. Benelux Line
You cannot wait for Germany to invade Benelux countries. At least 30 divisions must be put in Belgium borders. Then I always delete the frontline because divisions may move in after Germany attacks. We cannot let our positions because it is impossible to defend Benelux countries.
So, how do we hold the line? Around late 1938, player must start building forts on the Belgium border. Minimum fort level recommended is 4 but 5-6 would be ideal.
3. Savoy Line
That is an interesting one. Italy border is full of mountains. So, your mountaineers must be placed on the savoy line.
Another thing is, Savoy border does not have enough supply. Which is a huge problem. Your armies cannot hold their line without supply. Because of that, you must build level 3-4-5 infrastructure and one supply depot at the upper savoy.
Then again, at least level 4 land forts must be build at this border. Maybe one or two anti air guns can be build too in the southern France air-zone. Northern France already has 8 anti air guns.
4. African Frontline
I always ignore this theatre because each and every one of the soldiers must defend mainland. Germany is really strong and I don’t want to get capitulated. However, you can still build some roads, railways and land forts in order to defend Italian Eritrea border. I just don’t think it is worth defending / sparing divisions.
HOI4 Defending Poland
Defending Poland against both German Reich and Soviet Union is impossible at this patch. However, I believe obsessed players might pull this off by abusing every possible glitch / cheese tactics. But unfortunately it would not be natural.
I would either join Comintern or Axis by following the relevant focus tree in order to survive between two beast. It is the easiest, smartest, and the most realistic scenario. Allies can not defend you against both German Reich and Soviet Union.
Of course you can create your own faction. But still, you need to defend yourself against both Soviet Union and Germany. Too many and too long frontlines makes it impossible to defend.
Anyway, best way of defending against Germany or any other nation is building forts and keeping frontlines as small as possible.