Renegade50
I was looking at a map of the Ukraine and the Dnieper River is a pretty good sized obstacle for the Russians. There are 9 or so major crossing that I saw in a quick look and I'd expect attempts by both sides to seize control of them. Even if the Russians just want the land to the East of the Dnieper River they can bottle up reinforcements by controlling or even dropping those bridges.
Kyiv or Kiev (however you want to spell it) sits right on the river so I can see why the Russians are attacking there in force.
