Terrain favour the defender
Defending infantry dug-in and are more protectet than the assaulting infantry that run on feet and are exposed to explotions and fire. And this is why it takes 3 infantry units to successfully attack 1 defending infantry units. But firepower also count, so a unit with heavy artillery and tanks can attack a unit wich have more men but no heavy weapons. Also an elite unit with highly trained men can attack a bigger unit with less trained men. But against equal units, the 3-to-1 rule is applying.
Now extreme terrain like mountains, swamps, forests and snow work in many ways.
*Mountains is impassable, and all movements are concentratet to passes, wich are easy to defend. The defender can simply blow up the pass and nobody can move through. And attacking a pass that is defendet will cost high price. That is why nobody ever attacked through the Brenner Pass. I have been on vacation in the Alps, so I know.
As for the mountains in north Norway, the passes are closed by snow in the winter, and in the summer the passes turn into swamps with lots of mosquitos. The Norwegian mountains also are cut by fjords and rivers, so its very difficult to travel there even in peace-time. I should know since I served my time in the Norwegian Military Forces up there.
*Moving supplies through terrain with mountains, forests, swamps and snow are extremely difficult. Just look at the Northern Front in 1941, the German attack against Murmansk got booged down after 10 miles, at the river Litza, because it was impossible to move supplies there. As there is no roads up there, only a few muddy dirt-roads, all supplies had to be on ships, or carried on horse-back. So the gebirgs-jaegers didn’t have horses, and had to carrie everything on back-pack on their own feets. And when the russians attacked in 1944, they used rein-deers to carry supplies.
Most of the men serving up north did not die from bullets. They died from frostbite and cold, freezing to death, or starving from lack of supplies. In the summer they got eaten by mosquitoes. Even if the winter is only 5 months, the temp goes below -40 C in this period, and people simply freese to death. You should try this yourselves before comparing Norway to central europe.
*Snow works this way. In Finland and north Russia there is forest. This territories have dirt-roads and swamps and marshes, making the movement difficult. During winter, the snow actually makes it easyer to cross frozen marshes and rivers and minefields, and the snow also make artillery barrage less useful. All attacks must be done on skies, making man-to-man combat common.
How to put this into rules
- All defending units in mountains defend on 4 or less all time.
- All defending units in forest/snow defend on 3 or less, all time.
- All defending units in capitols defend on 3 or less all time, not just the first round.
- Defenders in plain and clear terrain defend as usual OOB
Also all units move only 1 space in territories with mountains, forest/snow and capitols.
I would like to split up the territories with terrain more, making Norway 3 or 4 spaces and Finland 2 or 3 spaces, to reflect the difficulties of moving in areas without roads or communicaation lines. But some people do it the other way, they split up little tiny UK-island into 5 areas, and make huge Norway and Finland one space. Thats bedlam if you ask me