What determines bridges in provinces?

Is there a way to tell whether a province will have bridge battles?

Or is there a list of provinces with bridges?

Is it random?

I defended Kiev from the Mongol hordes because I fought a bridge battle, but when the Poles and Mongols did an allied attack on Kiev, the map changed to one without a bridge.

Kiev has no river description.

If you rightclick on say georgia and move the mouse over to Khazar, you will se what type of battle there will be, like the terrain, hills or not and rivers or not.
This works on all provinces...

If you do as Snowhobbit proposes you will see a heading called Waterways. As far as I can see all provinces show "None" under that heading, with the exception of Valencia which shows "River". There may be other provinces with waterways but I haven't seen any.

Still you sometimes get bridge battles in provinces with no waterways and sometimes you don't get bridge battles in Valencia, although that's rare. It would therefore seem to be random but with different probabilities for each province.

Thanks, I didn't know that, that the terrain you get depends on where you are attacked from. The Poles attacking from Moldavia caused the battle to be fought without a bridge.

Those guys ruined my kingdom. Now the Mongols are attacking my other provinces without the disadvantage of bridge.

Playing Russia high isn't that easy now.

These are not random but are written in the campaignfile. For example (not exact but simplified for reading):

KIEV to KHAZAR: river flatland
KHAZAR to KIEV: flatland

So one way you will always have a bridge battle, but the other around not. If you want to know before a battle what the general terrain is, then follow SnowHobbit's instructions. Then you will also wether it's hilly or flat.

Sometimes these provinces link, so you can have a row of provinces that are all defended by bridge battles. Might be usefull for setting up a defensive strategy.

Cheers, Duke John

Also if the province is invaded from more than one province I believe that the battle depends on where the leadr of the invasion comes froms, for example whenever I invaded Valencia from Aragon I always got a bridge battle, but not when I invaded from Castile. So what I often do is move in the multi-starred genral unit alone from Castile to Valencia, and the rest of the invasion army from Aragon to Valencia, and avoid fighting on a river.

hell, I set up my defences against the horder - the only time I've actually met them - based on the rivers and the rivers only. You can defend 4 provinces in a thin blue line Kiev right round, and mass a larger cav and pavise based force in the province north of Khazar. Gotta kill the horde quick though, that level of armies was a serious drain.

But the horde were a huge disappointment. only 3 full stacks, and one of those was siege engines.

So I moved in with everything, drove off the main force and trapped the Khan in the Crimea with 2 units of MHC. then kept him there, raiding once in a while with my jedi general (9*, skilled attacker) to make sure he wasn't going anywhere with his army.