Ask the zealots

[Leyrann]

Do we know if there's a penalty for attacking from a river tile? Otherwise the only way to defend a river crossing is by counter attacking, which is a bit weird? And attacking along the same river would benefit the attacker, which is also odd.

I imagine that the point is that you have to end your turn when moving onto a river, which simulates crossing it, and during the crossing you're vulnerable to being attacked, so that's when the time to strike for the opponent is - hence, a defensive penalty.

After all, the difficulty in "attacking" over a river isn't that you can't attack... it's that the enemy has free reign to attack you before you're ready.