Sidways Chess

White to move. Does either side win by force?

Q on g1 - d4

Aaaaaa! My brain!

Do the pawns on b8 and g1 promote instantly?

No

Why not?

If no pawn can be moved the game must be a tedious knight only battle until one of them falls in the pawn area.

Yeah, but who ultimately wins?

It's not sideways chess if they do.

The only winners are the people who didn't read this thread.

Assuming no blunders are made, the game will be a draw.  Here is how I arrive at this conclusion:

1.  At the beginning of the game, only the knights and rooks are capable of moving.  Only the knights can leave the a- and h- files.

2.  The only way to change this situation is to capture a piece with a pawn or capture a pawn.

3.  Whoever gets any of their pieces freed up first will have, if not a win, at least a much greater chance of winning.  Therefore, neither side wants to free up any of their opponent's pieces.

4.  There is a way to checkmate on f3 or c5. For example, if the pieces are positioned correctly, White can move a knight to c5 with check, have it be captured by the b6-pawn, and recapture with the other knight, resulting in smothered mate.  However, this attack requires two knights, whereas only one is needed to defend.

5.  Therefore, in order to win in this way, a player first needs to eliminate both enemy knights while retaining both of his own.  The opponent, however, can prevent this by placing his knights in such a way that they are protecting both each other and the vulnerable f3/c5 square.  (For example, Black can accomplish this by playing Nc3, Nc8, Nd6, and Nce4.)  He can then move his rooks back and forth to his heart's content.

The game can be summarized as follows:

a) Either side can force a draw; and

b) It takes fewer moves to prevent a loss than it does to threaten a win.

Thus, a game will play out in one of two ways.  Either one player will play for a draw (and achieve one), or both players will try for a win.  If the second scenario occurs, eventually one of the players will threaten an immediate win, which the other will then have to prevent.  The defending player will have to abandon his attack, but he will be successful in preventing a loss.  He will be forced to begin playing for a draw, which turns the game into an instance of the first scenario.