All chess players should know that two knights alone can’t force checkmate. However, if you give the defending side one pawn, sometimes the knights can force checkmate because the single pawn’s ability to move prevents a stalemating defense.
To begin the checkmating sequence, the attacking side must start by placing their knight in front of the pawn. Which square the remaining pawn needs to be blockaded on is crucial for success and we can determine this without calculation by memorizing the possible pawn positions of of what is commonly referred to as the Troitsky Line.
The possible pawn positions for the Troitsky Line from Black’s Perspective.
Steps to Checkmating with Two Knights Using the Troitsky Line:
1. Place a Black Knight in front of the pawn on one of the squares shown above.
2. Push the White king to the corner of chessboard with the other knight and king.
3. Use the blockading Knight to force checkmate.
Now let’s see how the Troitsky Line worked in FM Rupert Jones (Papua New Guinea) vs. Joel Gavarrete (Honduras) from Round 2 of the 45th FIDE Chess Olympiad in Budapest. We join their game in time for Black’s 79th move. Notice that white’s pawn is already held in place on a5 which is one of the key squares for this maneuver. Now watch how White’s king is forced to the corner before the pawn is set free so that the other knight can help deliver checkmate.
