Hi. Coach Russ, here, with Chess NYC and we're going to look at the king
and rook checkmate. When looking at this position, it is actually
impossible to create a position where the king and the rook checkmate the
king in the center of the board.
So, that leaves us with four options. In order for the king and rook to
checkmate on the opponent's king, the opponent's king must be on one of the
four sides of the board.
The H file, the first rank, the A file or the eighth rank. And once the
opponent's king is on one of these sides of the board, it's possible for
the king and the rook to checkmate the king.
Now, let's look at an ending position. In a position such as this, the
opponent's king is on the side of the board and now it is possible for
white to execute a checkmate. In this particular position, the white's
king has created something called opposition. Opposition, meaning the
white's king controls all three of the escape squares of the opponent's
king in front of the king. The white's king controls F7, E7, and D7.
Therefore if the white's king was able to execute a check, it would leave
no other option for the king, but checkmate. White can simply play, rook
goes down to A8, check on the king. And due to the opposition and the
white king controlling F7, E7, and D7, all three squares in front of the
king, this is simply a checkmate.
Now, how do we force the opponent's king to one of the four sides? We are
going to try to improve the position where the space of the king and the
rook versus the king. And first and foremost, we would always like to
improve the position of the rook first or take more space.
So in looking at this position as a starting position, where can white's
rook go to improve its position to the maximum amount and control the most
space? In this position, white's rook is simply going to position C6. In
this position, as you can notice, it controls the whole C file and the
sixth rank giving black's king only this area to maneuver.
If black's king were to go down one square, we're going to improve the
position. We should always, like I said before, improve the position of
the rook first. And in this position, we can improve the position of the
rook in two different ways. We can improve the rook position, here, taking
away from the C file and now we control the B file or we can go and play
C5. Instead of controlling the sixth rank, we are going to control the
fifth rank. In this position, we are going to play this move. Black
responds and black plays king A5.
Now, we have to see if we can improve the position again. Is there any
where that this rook can improve its current position? And the answer is
no. There is no where that this rook can go that's going to give it
greater space. So now, we look at the king and we make a move and improve
the position with the king. Black's only response is for the king to come
And once again, how do we improve the position? First, we look at the
rook. We are able to take more space with the rook giving black's king one
response. And now, can we improve the position with the rook? And the
answer to this question, there's no moves for the rook that's going to take
more space. So, that gives us a second option. You can improve the
position with the king.
In this position, the king's going to come over. Once again, how are we
going to take more space and can we take more space with the rook? And,
the answer is no. So, we'll look at the second option; take more space
with the king. King comes down. And I ask you this question; can we
improve the position with the rook? And this answer, yes. We can take
more space. King has one option, is to go to A2.
And now we have to ask ourselves, can we improve the position with the
rook? Answer is yes, we can take more space. Once again, king comes down
and we ask ourselves again, can the rook improve the position? The answer
is no. There's no where this rook can go to take more space. So, the king
comes down and once again, the king takes space. King's only move is to go
up. And now we're in a situation where we need to begin to calculate.
We've gotten the king in very close quarters and we have to execute a
checkmate. The king went up. Can we improve the position with the rook?
And the answer is no. We can take no further space. So, we improve the
position with the king. Black's only response is the king come down.
And now in this position, we're going to see how we're going to improve the
position to the maximum. In this case, the maximum position is a checkmate
for white. So looking at this position, white simply plays rook A3. And
this is a checkmate. White controls these escape squares. White's rook
executes a checkmate and the game is over.
So in this position, we have forced the king into the corner. We've
improved the position, first, with the rook. And if there's no improvement
with the rook, we've improved it with the king, forcing our opponent's king
to one of the four sides of the board. And eventually, we are going to be
executing a checkmate.