Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5

Ruy López / Spanish game C60—99 King's Knight Opening 3...a6 · Morphy's defence 3...Nf6 · Berlin defence 3...d6 · Steinitz defence 3...Bc5 · Classical defence 3...f5 · Schliemann (Jaenisch) defence 3...Nd4 · Bird's defence 3...Nge7 · Cozio defence 3...Qf6 · Frankfurt defence 3...Bb4 · Alapin defence 3. Bb5 · Ruy López or Spanish game 3. Bb5 is known as the Ruy López opening or Spanish game. White threatens to trade off Black's c6 knight, the defender of e5, so indirectly threatens to win the pawn, though it's not an immediate threat because of a tactical trick where Black can win the pawn back. White is playing for quick development (they are ready to castle already) and control of the centre. They'd like to eventually play c3 and d4 to build a pawn majority in the centre. Usually, Black wishes to play ...Nf6, which develops a piece while threatening to take White's undefended e4 pawn, so the most common lines are to develop the knight straight away (3...Nf6) or after first kicking the bishop (3...a6 usually followed by 4...Nf6). However, Black has a wide range of turn three or turn four sidelines to choose from so can respond in a variety of ways. Morphy defence 3...a6, the Morphy defence, forces White to make a decision about the bishop: retreat, or exchange. The oldest continuation is to take the knight, 4. Bxc6, the Exchange variation. This doesn't win the e5 pawn, however (4...dxc6 5. Nxe5? Qd4! and Black can win the pawn back). The Exchange variation is playable, but more popular is 4. Ba4, preserving the bishop pair and pressure on Black's knight. After 4. Ba4, the main line is 4...Nf6, as in the Berlin. However, by including 3...a6 4. Ba4, Black now has the option of cutting off the bishop's pressure whenever they wish with ...b5. Berlin defence 3...Nf6, the Berlin defence, is the main sideline. Recognising there is no immediate threat to their pawn centre, Black develops and threatens ...Nxe4 instead. The Berlin has a reputation for being solid but very drawish. The opening often leads into a quick exchange of queens and equal endgame (the Berlin Endgame) or a fast draw by repetition. 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 Morphy's defence 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 Berlin defence Principal sidelines Many other moves are available, some neglecting completely the protection of the knight and the pawn and continuing development. The two next most commons sidelines in master-level play are 3...f5!? and 3...g6. 3...f5!?, the Schliemann or Jaenisch gambit, is a sharp line where Black attacks White's centre from the flank. Accepting with 4. exf5 allows 4...e4. The usual response is 4. d3, which renews the threat of 5. exf5 because the pawn on d3 prevents 5...e4. 3...g6, the fianchetto or Smyslov defence, prepares a king-side fianchetto, although often Black delays actually playing ...Bg7 until they have played ...d6. 1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 Schliemann defence 1. e4 e5 2. Nf3 Nc6 3. Bb5 g6 Fianchetto defence In amateur games, more common sidelines are 3...Bc5 and 3...d6. 3...Bc5 is the Classical variation. Since there is no danger to e5 yet, Black simply develops the bishop to pressure White's kingside and the vulnerable f2 square. This is one of the oldest defences. 3...d6, the Old Steinitz defence, was the continuation recommended by Wilhelm Steinitz. Playing 3...a6 and later b5, he reasoned, just allows White's bishop to get to where it would like to go: to man the dangerous b3-to-f7 diagonal. Steinitz advocated 3...d6 instead to defend the e5 pawn directly. However, this is passive, inhibiting Black dark square bishop, and Black self-pins their knight: White's most critical reply is 4. d4. A "Modern" Steinitz defence delays ...d6 until after 3...a6. 1. e4 e5 2. Nf3 Nc6 3. Bb5 Bc5 Classical variation 1. e4 e5 2. Nf3 Nc6 3. Bb5 d6 Old Steinitz defence Minor sidelines Other lines have been tried. These include, in rough order of legitimacy: 3...Nge7, Cozio defence, defending the knight with the other knight. 3...Be7, the Lucena variation, likely to transpose to the main line closed variation after 4. O-O a6 5. Ba4 Nf6. 3...Nd4!?, Bird's defence. Black counterattacks the bishop: after 4. Nxd4 exd4 Black has gained some space but has slightly worsened their pawn structure. 3...Nb4?! is a rare trap tried once by Marshall where 4. Nxe5? is met with 4...Qg5!. 3...f6?!, the Nürnberg variation, defending e5 but at the cost of severely weakening Black's kingside. 3...Bb4?!, the Alapin defence. 3...Qf6?!, the Frankfurt defence. 3...d5?, the Spanish countergambit. Black hopes to bamboozle White by offering them a choice of centre pawns to capture. 3...a5?!, the Bulgarian variation, looks like a mis-click. Perhaps the idea is 4. O-O Nd4 5. Nxd4 exd4 where a careless 6. d3? c6 7. Bc4 b5 traps White's bishop. 3...b6?!, the Rotary-Albany gambit. 3...Qe7?, the Vinogradov variation, defends the e-pawn with the queen. However, on e7 the queen blocks development of Black's king side bishop and runs into a dangerous x-ray after 4. O-O Nf6 5. Re1. It may be played with the idea 4...Nd8 and 5...c6. 3...Nb8?, the humorous retreat variation. 3...g5?, the Brentano Gambit. 3...Na5?, the Pollock variation, sidestepping the bishop's vision. 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nd4 Bird's defence 1. e4 e5 2. Nf3 Nc6 3. Bb5 d5 Spanish countergambit 1. e4 e5 2. Nf3 Nc6 3. Bb5 Qe7 Vinogradov variation 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nb8 Retreat Variation 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nge7 Cozio Defence 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nb4 Nb4 sideline 1. e4 e5 2. Nf3 Nc6 3. Bb5 Bb4 Alapin Defence 1. e4 e5 2. Nf3 Nc6 3. Bb5 f6 Nürnberg Variation 1. e4 e5 2. Nf3 Nc6 3. Bb5 Qf6 Frankfurt Defence 1. e4 e5 2. Nf3 Nc6 3. Bb5 Be7 Lucena Variation 1. e4 e5 2. Nf3 Nc6 3. Bb5 g5 Brentano Gambit 1. e4 e5 2. Nf3 Nc6 3. Bb5 a5 Bulgarian Variation 1. e4 e5 2. Nf3 Nc6 3. Bb5 b6 Rotary-Albany Gambit 1. e4 e5 2. Nf3 Nc6 3. Bb5 Na5 Pollock Variation History The earliest known analysis of this opening is from the 15th century Göttingen manuscript. The 16th century Spanish priest Ruy López de Segura analysed the opening in his 1561 book on chess, from which both the modern names Spanish opening and Ruy López derive. Ruy López de Segura considered the danger posed to Black by 3. Bb5 to be so severe that it refuted 2...Nc6, and recommended 2...d6 to Black instead. In the 18th century, the "Modenese masters" Ercole del Rio and Domenico Lorenzo Ponziani analysed the exchange variation of the opening (3...a6 4. Bxc6) and concluded that the bishop was better placed on the c4-to-f7 diagonal (i.e. 3. Bc4, the Italian game). In the mid-19th century, Carl Jaenisch published detailed analysis of 1. e4 e5 in French and English circulars. Writing "this opening has been strangely overlooked and passed by, we may say in contempt, by all writers", Jaenisch's treatment of 3. Bb5 reinvigorated interest in what he called "Lopez's Knight's Game". Jaenisch was dismissive of the defences 3...Nge7 (Cozio defence) and 3...Nd4 (what we now call Bird's defence), and especially critical of del Rio and Ponziani's analysis (which he called "very defective"). Jaenisch's treatment of 3...a6 reads as very modern:Carl Jaenisch 1848 Major Jaenisch On Ruy Lopez' Knight's Game Chess Player's Chronicle 9 216-21,248-53,274-79 https://www.google.ch/books/edition/The_chess_player_s_chronicle/ja5AAAAAcAAJ?hl=en&gbpv=1&pg=PA216 9 June 2025 White's correct move is simply to withdraw the attacked Bishop to [a4], preserving its menacing direction. This shows that the move, [3...a6], is absolutely useless, for if Black follow it up with [4...b5], White's Bishop is brought into a good line of attack on [b3]... We may remark in general, that the object of [3. Bb5] is not to double a Pawn for Black by taking his [Knight], but to confine the development of his right wing as long as possible; and it is precisely in order not to allow him to escape from the confinement that the Bishop, if attacked by [a6], either at the third or any subsequent move, must not take the [Knight] but retire to [a4]. This was the beginning of the modern Spanish main line. In 1918, Frank Marshall introduced an aggressive turn 8 gambit that reinvigorated Black's attacking chances in the closed Spanish. The next major shake up occurred in the 1960s when new theory in the Marshall gambit drove White players to adopt anti-Marshall systems to avoid it. In 2000, the main alternative to 3...a6, 3...Nf6, was re-popularised when Vladimir Kramnik used it as a drawing weapon against Garry Kasparov during his successful World Championship challenge. Nowadays the Spanish opening is known as one of the most deeply studied and popular chess openings, and one of the most frequently seen at the highest levels of chess. It is the continuation of the Open Game most commonly seen in master-level play, adopted by virtually all players at some point in their chess career. Theory table 1. e4 e5 2. Nf3 Nc6 3. Bb5 3 4 5 6 7 Eval Morphy Defence ...a6 Ba4Nf6 O-OBe7 Re1b5 Bb3O-O = Berlin Defence ...Nf6 O-ONxe4 d4Nd6 Bxc6dxc6 dxe5Nf5 = Smyslov Defence ...g6 c3a6 Ba4d6 d4Bd7 O-OBg7 += Classical Defence ...Bc5 O-ONd4 Nxd4Bxd4 c3Bb6 d4c6 += Schliemann Defence ...f5 Nc3fxe4 Nxe4d5 Nxe5dxe4 Nxc6Qg5 += Bird's Defence ...Nd4 Nxd4exd4 O-OBc5 d3c6 Ba4Ne7 += Steinitz Defence ...d6 d4Bd7 Nc3exd4 Nxd4g6 Be3Bg7 += Cozio Defence ...Nge7 O-Oa6 Bc4b5 Bb3d6 d4h6 += Vinogradov Variation ...Qe7 Bxc6dxc6 d4Bg4 dxe5Bxf3 Qxe5Qxf3 += Ruy Lopez References