[Event "The Problemist"] [Site "?"] [Date "2018.??.??"] [Round "?"] [White "Rusz, Árpád"] [Black "(Study 144)"] [Result "1/2-1/2"] [SetUp "1"] [FEN "1KB1n3/3p4/2bP4/8/3pk3/1N6/8/8 w - - 0 1"] [PlyCount "17"] 1. Bxd7 $1 (1. Nc5+ $2 Kd5 2. Nxd7 Nxd6 3. Nf6+ Kc5 $1 4. Nd7+ Bxd7 5. Bxd7 { Position X'} d3 $19) 1... Bxd7 2. Nc5+ {The knight leaves the b3 square, but it will return there after a long trip.} Kd5 3. Nxd7 Nxd6 (3... Kxd6 4. Nb6 d3 5. Nc4+ Kc5 6. Nd2 $11) 4. Nf6+ $1 (4. Nb6+ $2 Kc6 $19) 4... Ke6 (4... Kc5 5. Nd7+ {Position X - The knight proves to be more efficient than the bishop in the fight against the passed pawn.} Kd5 (5... Kc6 6. Ne5+ Kd5 7. Nd3 $11) 6. Nf6+ Kc5 (6... Kc4 7. Ng4 d3 8. Ne5+ $11) 7. Nd7+ {perpetual check}) 5. Nh5 $1 {This extra file was missing from the other flank.} Kf5 (5... d3 6. Nf4+ $11) 6. Ng3+ Kg4 7. Nf1 $1 {The knight has to stop the pawn before it reaches d2.} ( 7. Ne2 $2 d3 8. Nc3 d2 $19) 7... Kf3 8. Nd2+ Ke2 9. Nb3 $1 {During the trip, the knight drew a big square on the board!} 1/2-1/2