In the game of Spades, if two players from opposites partnerships bid 0 (Nil), then the round plays very different from a regular round, each of the non-Nil players try to set the opponent Nil without setting her partner.
Except maybe the first trick, only cover-players will lead tricks (since nilers avoid winning tricks, and if a nilers wins a trick the round become a single nil round).
The nilers are adjacent. This gives advantage to one partnership:
- the cover-partner that plays before both Nilers, has a disadvantage, she don't know if she should play high card to cover her partner or she can play a low card to try setting her opponent's nil.
- The cover-partner that plays after both Nilers has an advantage since she can see if she needs to cover or not.
I build an AI player of Spades, and I want to add this special case of Nil Vs. Nil round. My question is, what are the main strategy considerations, or what adjustments in game play should I add? For refining reasons, assume its the first round of the game.
 Nil Vs Nil rounds are not too rare in normal games. In the Suicide variant, every round is a Nil Vs Nil round.
 Occasionally, Nil Vs. Nil rounds happens at a "game winner round", that is to say, one partnership will win the game if she makes the Nil. In this kind of situations, other considerations come in to play. In order to refine the question, assume this is the first round of the game.