Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nf6

Russian game King's knight opening C42-43 3. d4 · Modern attack 3. Nxe5 · Classical variation 3. Bc4 · Italian variation 3. Nc3 · Three knights 2...Nf6 · Petrov's defence or Russian game Rather than defend e5, Black counterattacks e4. This is the Russian game, aka Petrov's or Petroff's defence, a solid if drawish opening.60% of games in the Lichess masters database result in draws, compared to 50% for 2...Nc6. White's typical plan is to attack the centre, usually leading to a trade of pawns. Alternatively they may gambit their e4 pawn, or defend it and perhaps hope for a transposition. Trade e pawns 3. Nxe5 is the main line, the Classical variation. As Black didn't defend their pawn, White takes it. Black can recover it, but not immediately on account of dangerous tactics resulting from 3...Nxe4!? 4. Qe2!, exploiting the open e-file (including the famous trap, 4...Nf6?? 5. Nc6+ winning the queen). The best line is 3...d6, chasing White's knight away, after which 4...Nxe4 is safe because if 5. Qe2 Qe7 defends the knight. 3...Nc6?!, the aggressive Stafford gambit, is the most common reply in amateur games. Black gives up a pawn for open lines and a sharp attack. 3. d4, the Modern attack, was advocated by Steinitz.Modern Chess Instructor Steintiz Wilhelm G. P. Putnam's Sons 1889 London 116-139 Of the two captures, 3...Nxe4 is most common. 3...exd4 is playable but after 4. e5 Black falls behind while their knight gets kicked about (4...Ne4 5. Qxd4 d5 6. exd6 Nxd6+). Gambit e4 3. Bc4?!, the Italian variation, leaves White's e4 pawn undefended. It's usually played with the idea of sacrificing it for development: 3...Nxe4 4. Nc3?!, the Boden-Kieseritzky gambit. Instead, 3...Nc6 transposes into a Two knights defence of the Italian game. Defend e4 White may wish to prevent ...Nxe4, though taking the time to defend their pawn gives Black the chance to defend theirs too. 3. Nc3, the Three knights variation, is a sound sideline. White develops a piece and invites Black to transpose to a Four knights with 3...Nc6 and avoid the Petrov main lines. 3...Bb4 avoids transposing, pressures the knight on c3 and makes the game a little more active. 3. d3 is, according to statistics, much more effective than it looks. White builds a strong fortress and Black must now defend his pawn. The game usually ends up looking like a Hanham variation of the Philidor with colours reversed (3...Nc6 4. Be2 d5 5. Nbd2 Bc5 -) or White adopts a King's Indian attack-style setup with g3 and Bg2. History 2...Nf6 is a very old opening, appearing in the 15th/16th century Göttingen manuscript, the earliest manuscript dedicated to modern chess. However, it was largely overlooked until the 19th century. Jaenisch (1813―1872) levels (his typical, bombastic) criticism at previous attempts to characterise the opening in his 1842 bookJaenisch's chess preceptor: a new analysis of the openings of games de Jaenisch C. F. Longman & co. 1847 London https://babel.hathitrust.org/cgi/pt?id=hvd.hn52dv&seq=5 Walker George (translation of Analyse nouvelle des ouvertures du jeu des échecs de Jaenisch C. F. Gartner 1842)126-147: The fate of this opening has been somewhat "bizarre." Proclaimed faulty from the 16th century (compare Damiano, Lopez, and Gianutio), it has been entirely thrown on one side, and has only since appeared in the books; which content themselves with reproducing, without change, the ancient analysis of the classics. Cozio, in truth, that frivolous genius, who saw everything superficially, without diving into it, at last briefly corrected the fallacies of the original analysis in question; but, curious enough, was not himself aware of the importance of his observation, which passed altogether unnoticed by later writers.—Carl Jaenisch (translation: Walker) It was Alexander Petrov (1794―1867) and Jaenisch's analyses that led to the rejuvenation of opening in the 19th century (and it's after these two Russians the opening gets its appellation). Jaenisch highlights Petrov's independent (re-)discovery of Cozio's 3. Nxe5 d6! (over 3...Qd7). Jaenisch also credits Petrov with 3. d4 as White, the line later advocated by Steinitz in his 1889 book. Theory table 1. e4 e5 2. Nf3 Nf6 3 4 5 6 7 8 9 10 11 12 13 14 15 Classical Variation Nxe5d6 Nf3Nxe4 d4d5 Bd3Nc6 O-OBe7 c4Nb4 Be2O-O Nc3Bf5 a3Nxc3 bxc3Nc6 Re1Re8 cxd5Qxd5 Bf4Rac8 = Steinitz Variation d4Nxe4 Bd3d5 Nxe5Nd7 Nxd7Bxd7 O-OBd6 c4c6 cxd5cxd5 Nc3Nxc3 bxc3O-O Qh5g6 Qxd5Qc7 = Two Knights Defence Bc4Nc6 = Four Knights Game Nc3Nc6 = d3Nc6 = References See also Petrov's Defence