[0x138d5]

Also this ratio is a guide for open terrain. In closed terrain and urban combat the defender has a greater advantage.

[FredPret]

The famous 300 Spartans did a lot of damage partly because they used the terrain to limit the size of the front

[IIsi50MHz]

I seem to recall learning that the famous 300 Spartans also had another ~3000 Greeks in with them. Is the poplular tale of "only" 300 Spartans not a popular myth perpetuated because it sounds cooler?

[number6]

This is why you should use mountains to defend if you are attacked by a greater force in EU4. Smaller combat with.

[AtlasBarfed]

And Civ1. And Civ2. And D&D War Machine.

If you have a combat sim and it doesn't reward hills/mountains for defense, then you are playing a space sim.

[kqr]

This is a consequence of a more general principle: the ratio refers to the effective concentration of force at the time of battle.

It doesn't matter how big your force is if you can only get a trickle going into battle. Then you will constantly be outnumbered where it matters.

Similarly, in urban combat it's very hard to actually get a 3:1 effective concentration when you are moving in on someone else.