From page 7 of the Rules:

"A Fleet that can move to a province with two separate coasts (a Fleet in the Mid-Atlantic, for example) can support another Army or Fleet into that province (in this case Spain), without regard to separate coastlines."

@Kingdroid, @FatherSnitch: That's not a great example-- a better example would be Fleet Gascony supporting Marseilles to Spain (south coast).

The answer to both the OP's question and my example is that coast does not matter in supports to a two-coast territory-- the only criterion is you can support a unit to move to a territory that you can move to.

Going the other way, F Bul/nc would not be able to support a move to Greece because F Bul/nc can't move to Greece.

what Katsarephat said.

It's an interesting rule, isn't?

On one hand, one could reasonably argue that the rule shouldn't allow it.

However, on the other hand, that would significantly nerf the effectiveness of naval power surrounding the 3 double-coast provinces, all of which are certainly pivotal in the game.

Thanks, its an interesting rule. Definitely one that exists for pragmatic reasons and not logical ones.

No, it's completely logical. Support means you can harrass the unit being attacked and divide it's forces. If you are forcing a unit to split it's defense over two coasts, then it is just as weak as if it had to fight two units off the same coast. Divide and conquer. See? Perfectly logical.

I find a F N Coast St Pete's successfully defending against an army in Moscow much more illogical. Or an A Norway moving to St. Pete's, having seen the terrain near the Norway/Russia border. But that's because I'm imposing the real world on a game, and the game says that the only requirement for supporting is being able to move to the target province, not the target coast.

I mean. A Serbia can't go to the north coast either, but he can support you in.

I generally agree with your point, Draug, but how does a defending fleet split its defenses across two coasts? Of course, one could imagine that land-based support staff is stretched, or that morale is drained by the other coast being pillaged, or that commandos are dropped to move toward the other coast, and so on, etc.

However, Diplomacy is a very abstract game, and I think the rules are and necessarily must be more motivated by practical game play reasons than realistic war simulation. At some point, one has to make these choices in abstraction. For example, consider the issue of two fleets trying to switch places like this: Por -> Spa(sc), Spa(nc) -> Por.

Agreed. The reules are meant to simulate real combat or there would be accomodations for types of troops/strength of the unit. Things like unit losses that hadn't been replaced and supply lines being cut would come into play. No, the game is an abstract game on a map, in this case, set around WWI Europe, Russia, and the Med.

Basically, I think it's silly to worry too much about the logic or realism of the rules. It's better to simply appreciate the subtle forethought of their design.

Even the geography is interesting. Consider what an impact the presence of Heligoland Bight has on the dynamic of that area. It's a buffer, it impacts the availability of the North Sea, it's a foothold for supporting attacks, it's a retreat option to keep fleets alive, etc.

I think that the Norway-StP connection provides a vital link to open up movement in the north.

Yes. What I love about the rules is that as much as they are somewhat based in logic and reality, they also toss it out the window in favor of gameplay. That's the beauty of it.