Botvinnik's rule

Botvinnik's rule expresses a practical idea: endings in which both sides retain a knight and pawns often behave like pawn endings. Knights have short range, need several jumps to change sectors, and cannot easily lose a tempo, meaning make a waiting move that leaves essentially the same position.

King activity, passed pawns, which have no enemy pawn ahead on their own or either neighboring file, and promotion races, in which both sides calculate which pawn will reach the last rank first, therefore become especially important. Zugzwang also appears often; it is a position in which the obligation to move makes matters worse. As in a pawn ending, the king that enters first or a distant passed pawn may force the opponent to abandon another part of the board.

The rule does not mean the knights can be ignored. A knight can blockade a pawn, give checks, and create a fork, an attack on two or more targets in one move. Players must also calculate the consequences of exchanging knights, because the resulting king and pawn ending may be won, drawn, or even lost.

Use the rule as an order of thought. First evaluate kings, passed pawns, possible pawn breakthroughs, meaning sequences of advances or sacrifices that clear a path for a pawn, and promotion races as though studying a pawn ending. Then add the knights' concrete jumps, checks, forks, and exchanges. The phrase guides evaluation, but it does not replace calculation or endgame theory, the study of exact results and methods when few pieces remain.