[Sensori]

They can't. And even sailing units can't cross multiple water provinces, it'd have to be one big province for them to cross it. So if some poor bastard started from the corner, he'll be fighting the water nations for the most part, but on the other hand he'll be very safe from attacks by proper ground forces...

Unless more than 1 guy started from the corner. Now THAT'd be bad for them, considering that it'd give us more provinces (good for us) while they're fighting over a rather nominal number of provinces (bad for them).