Endings 6, 7 & 8
The rook-pawn drawing rule completed, then the wrong and right corners in Rook vs Bishop, and the fundamental defensive principle in Rook vs Knight: keep the king and knight together.
We continue from Position 1.16. Black's only chance is to prevent the white king from getting in front of the pawn.
Position 1.16 · Rook-pawn drawing rule · White to move
FEN: 8/8/8/p7/8/1k6/8/2K5 w - - 0 1 · Key squares: c1, c2
The marked squares c1 and c2 are the bishop-file squares next to the promotion corner a1. White can hold the draw by occupying one of them.
Main line — Black pushes the pawn
This reaches the well-known drawn rook-pawn position.
Main continuation — White holds
White prevents the black king from escaping the corner.
Continuation
Nothing can be done. The black king cannot escape, and pushing the pawn immediately stalemates the king.
Variation
Even several doubled rook pawns would not change the result.
Rook vs Bishop is normally drawn, but becomes dangerous when the defending king is trapped in the wrong corner.
Black is trapped in the wrong corner. White wins by forcing the bishop out.
Position 1.17 · Rook vs Bishop: The Wrong Corner · White to move
FEN: 6k1/5R2/3b2K1/8/8/8/8/8 w - - 0 1
The black king on h8 is trapped in the wrong corner — the same colour as the bishop on g1. White wins by forcing the bishop out of its safe squares behind the white king, then gaining the decisive tempo needed for mate.
Winning move
Main line
The rook gradually removes the bishop's safe squares.
Continuation
Finish
Variation
Black can no longer prevent the mating threat. The rook has restricted the bishop to the fatal diagonal.
The opposite corner completely changes the evaluation. The bishop has enough room to interpose, making the ending a theoretical draw.
The bishop can interpose on g8, giving Black drawing chances.
Position 1.18 · Rook vs Bishop: The Right Corner · White to move
FEN: 7k/R7/7K/8/8/1b6/8/8 w - - 0 1
The black king on h8 is in the right corner — the opposite colour to the bishop on b3. The bishop can interpose on g8 along the long diagonal, giving Black drawing chances.
Main line
White must eventually release the pressure to avoid stalemate.
Continuation
Variation
Another variation
The bishop always has enough squares available along the long diagonal.
Although Rook vs Knight is generally drawn, the knight must remain close to its king. If separated, the knight may be lost.
Being driven to the edge is usually not fatal. The real danger comes when the knight becomes separated from its king.
Position 1.19 · Rook vs Knight: king and knight together · White to move
FEN: 8/8/8/8/8/3k4/r7/3NK3 w - - 0 1
The knight on e1 and the white king on f1 are together on the edge. The black rook on a2 and king on d3 press for separation. The main danger is the knight being driven away from its king.
Main line
The knight returns to the king. This is the only temporary separation before king and knight reunite.
Variation
Again the knight rejoins the king. The defence holds as long as the two pieces stay within reach of each other.