bridge battles suck imho. for a few reasons. the map always looks more or less the same with a bridge in one corner and a shallow in the other and an island in the middle. it is always a straight river without any meanders. but besides that it is easy to defend it and the AI barely ever occupies bridges. when defending u just create a bottle neck with some artillery on schrapnel skirmishers and line on the flank. they march in and get ripped to pieces within moments. they almost always attack the shallow and leave the bridge... which is oke because the bridges are ridicilously narrow. no army general would march an army over there.