[Event "Shakhmatnaya Kompozitsia"] [Site "?"] [Date "2017.??.??"] [Round "?"] [White "Rusz, Árpád"] [Black "(Study 121)"] [Result "1-0"] [SetUp "1"] [FEN "4n2K/8/8/8/3k1P2/8/1P6/7N w - - 0 1"] [PlyCount "11"] 1. Ng3 {The knight takes the e4 square from the black king.} Nd6 (1... Ke3 2. f5 Kf4 3. b4 $1 Kxg3 4. b5 Kf4 5. b6 Nd6 6. f6 Ke5 7. b7 $1 (7. f7 $2 Nxf7+ $11 ) 7... Nxb7 8. f7 $18) 2. Kg7 (2. f5 $2 Ke5 3. Kg7 Nxf5+ 4. Nxf5 Kxf5 $11) 2... Ne4 {Now the white knight has to leave. Fortunately, the black king still cannot attack efficiently the f-pawn because the e4 square is blocked.} (2... Ke3 3. f5 Kf4 4. Kf6 $1 Kxg3 5. Ke6 $18) 3. Nh1 $3 {Switchback and a voluntary self-incarceration of the white knight!} (3. Nxe4 $2 Kxe4 4. b4 Kxf4 5. b5 Ke5 6. b6 Kd6 7. b7 Kc7 $11) ({1st thematic try:} 3. Nh5 $2 Kc4 4. Kf7 Kb3 5. Ke6 Kxb2 6. Ke5 {Position 1} Nf2 $1 $11) ({2nd thematic try:} 3. Nf1 $2 Kc4 4. Kf7 Kb3 5. Ke6 Kxb2 6. Ke5 {Position 2} Nc5 $1 $11 (6... Nf2 $2 7. f5 Ng4+ 8. Ke6 Kc3 9. Ne3 $1 $18 {echo sacrifice})) (3. Nf5+ $2 Kc4 4. Ne3+ Kd3 5. Nd1 Nd6 6. Kf6 Ke4 7. Kg5 Nf7+ 8. Kg4 Nh6+ 9. Kg3 Nf5+ 10. Kg4 Nh6+ 11. Kg5 Nf7+ { perpetual check}) (3. Ne2+ $2 Ke3 4. f5 Kxe2 $11) 3... Kd5 $1 (3... Kc4 4. Kf7 $1 Kb3 5. Ke6 Kxb2 6. Ke5 {Position 3} Nc5 7. Nf2 $1 $18) (3... Ke3 4. f5 Kf4 5. f6 Nxf6 6. Kxf6 $18) 4. f5 (4. Kg6 $2 Ke6 5. f5+ Ke5 {mutual zugzwang} 6. b4 Kd5 7. b5 Kd6 $1 8. Ng3 $1 Nxg3 9. f6 Ne2 10. f7 Nf4+ 11. Kf5 Ne6 12. b6 Nf8 13. b7 Kc7 $11) 4... Kc4 $1 {Only now! Kf7 is not possible anymore.} (4... Ke5 5. Kg6 $18 {mutual zugzwang}) 5. Kg6 $1 (5. Kf7 $2 Nd6+ 6. Ke6 Nxf5 7. Kxf5 Kb3 $11) 5... Kb3 6. Ng3 $1 {Echo sacrifice (see the 2nd thematic try). White repeats the first move from the initial position and wins.} (6. Nf2 $2 Nxf2 7. f6 Ng4 (7... Nd3) 8. f7 Ne5+ $11) 1-0