The Rule of the Square is absolutely essential endgame knowledge, but there are many other handy tricks that are worth knowing as well. One of them is the problem of the wrong colored bishop and rook pawn.
This position is a dead draw because White cannot force the Black king out of the corner. In endings with a bishop and an a-pawn or h-pawn, if the bishop moves on the same color as the queening square, the game is an easy win. If the queen moves on the opposite color, it is a draw (assuming that the defending king can reach the corner).
This can be an important drawing resource. A player who is down by a piece and a pawn may be able to draw if he can arrange the right exchanges. A player who is down by two pawns may sometimes achieve a draw by sacrificing his last piece for a pawn.
This was the position that Mike Momsen had against Fremd's Meyyappan Ramu on 5th Board. If Black grabs the pawn with 46...Qxb4, his drawing chances increase significantly because White has the wrong colored bishop for the h-pawn. If Black can manage to trade any one of his four remaining pawn for the White g-pawn, a queen trade would lead to a dead draw. Instead, Black played 46...Qe5+ and continued to put up stiff resistance leading White to eventually make a generous draw offer which Black happily accepted.
Defending an Inferior Position
One thing that pleased me greatly was the way that Mike Monsen on 5th Board and Nick Martin on 4th Board hung tough while down material. Too often, players who fall behind look for cheap traps to turn the game around quickly. When the trap doesn't work, their position falls apart quickly. Mike and Nick did it the right way. They maintained solid pawn structures and avoided giving their opponents any easy targets.
Defending an inferior position can be dreary work, but the goal is a simple one, stop your opponent from making progress on his next move. If you can do this for several moves, your opponent may start to wonder whether his advantage is as big as he thought it was or he may start to feel like his advantage is slipping away. He may start playing for a draw instead of a win or he may take unnecessary risks and blunder. For Mike it was the former. For Nick it was the latter.