Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5

Two knights defence C57 Italian game → 3...Nf6 4. Ng5!? 4. Ng5!? is a sideline but the most common amateur move. This Romantic move is an attack on f7 with the bishop and knight, taking advantage of the fact that Black gave up control of g5 and cannot castle yet. However, it is unprincipled to attack before having finished development and Black equalises with best play. Black needs to defend f7: otherwise, as in the common beginner blunder, 4...h6?? 5. Nxf7 Qe7 6. Nxh8, Black gets the house. If Black thinks to counter-attack instead, 4...Nxe4?, the Ponziani-Steinitz gambit, fails to 5. Bxf7+! Ke7 6. d4. 4...d5 is the best way to defend f7. This sacrifices a pawn to 5. exd5. Then there have been several moves tried: 5...Na5, the Polerio defence, is the most serious continuation and main line today. Black counterattacks the bishop, and the line continues 6. Bb5+ c6 7. dxc6 bxc6 8. Bd3 Nd5 9. Nf3 Bd6 10. O-O. White may be ahead a pawn, but Black is considered equal with more active pieces; 5...b5!?, the Ulvestad variation, to drive the bishop on c4 to somewhere less useful; 5...Nd4!?, the Fritz variation, gets the knight out from under the gun; 5...Nxd5?! is more common in amateur games, allowing 6. Nxf7, the audacious knight sacrifice known as the fried liver attack, or 6. d4, the Lolli attack. 4...Bc5? is the venomous but objectively dubious Traxler counterattack. Black can answer 5. Nxf7? Bxf2+! 6. Kxf2 Nxe4+, but instead 5. Bxf7+ is a free pawn. History This move has been known since the 17th century, appearing in attributed to Italian chess masters Giulio Cesare PolerioPolerio v Domenico, 1610. Chessgames.com and Gioachino Greco.Greco v NN, 1620 Their games continued with the line 4...d5 5. exd5 Nxd5 6. Nxf7, the fegatello, or in English, the "fried liver" attack. Colloquially, the position after 4. Ng5 may be called the "fried liver", or that name is reserved specifically for the continuation with 5...Nxd5 and the sacrifice of the knight on f7. This is a sharp attack on Black's weakest square, f7. A generous critic might call 4. Ng5 "forthright", though Siegbert Tarrasch called it "bungling".Tarrasch Siegbert Smith G.E. Bone T.G. The Game of Chess 1935 London Chatto & Windus https://archive.org/details/dli.ministry.13269/page/n5/mode/2up Internet Archive 259 In general, chess masters find 4. d3 to be more sound, however 4. Ng5 demands Black play accurately and at worse the game is equal. A recent appearance of 4. Ng5 was in the 2026 Women's Candidates, played by Zhongyi Tan.Tan v Goryachkina, 2026. Chessgames.com Theory table 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 4 5 6 7 8 9 10 Traxler Counterattack, Bishop Sacrifice Line 1 Ng5Bc5!? Bxf7+Ke7 Bd5Rf8 O-Od6 c3Bg4 Qb3Bb6 Bxc6bxc6 +/= Lolli Attack, Pincus Variation 2 ...d5 exd5Nxd5!? d4Bb4+ c3Be7 Nxf7Kxf7 Qf3+Ke6 Qe4Rf8 +/= Fried Liver Attack 3 ...... ...... Nxf7!?Kxf7 Qf3+Ke6 Nc3Ncb4 a3Nxc2+ Kd1Nxa1 -+ Polerio Defense, Kieseritzky, Yankovich Variation 4 ...... ...Na5 d3h6 Nf3e4 Qe2Nxc4 dxc4Bc5 Nfd2O-O = Polerio, Bishop Check Line, Suhle Defense 5 ...... ...... Bb5+c6 dxc6bxc6 Be2h6 Nf3e4 Ne5Bc5 ∞ Polerio, Bishop Check, Suhle, Steinitz Variation 6 ...... ...... ...... ...... ...... Nh3Bd6 d3O-O ∞ Polerio, Bishop Check, Bogoljubov Variation 7 ...... ...... ...... ...... Qf3Be7 Bxc6+Nxc6 Qxc6+Bd7 ∞ Ulvestad Variation, Kurkin Gambit 8 ...... ...b5 Bf1h6 Nxf7Kxf7 dxc6Qd5 Qf3Qc5 b4Qxb4 ∞ Fritz Variation, Gruber Variation, Berliner Variation 9 ...... ...Nd4 c3b5 Bf1Nxd5 Ne4Qh4 Ng3Bg4 f3e4 Ponziani-Steinitz Gambit 10 ...Nxe4?! Bxf7+!Ke7 d4d5 Nc3 += 11 ...Nd5 d3 += References Two Knights Defence