Ruy López

La Defensa Morphy (3...a6) es la respuesta más popular de las negras. Paul Morphy la empleó en la segunda partida ^{[ 14 ]} (un empate) y en la cuarta partida ^{[ 15 ]} (una victoria para Morphy) de su encuentro de 1858 contra Adolf Anderssen en París . ^{[ 16 ]} A principios de ese año, Morphy también se había encontrado con 3...a6 en una de sus partidas contra Johann Löwenthal en Londres . ^{[ 17 ]} La ​​jugada ganó posteriormente gran popularidad y fue nombrada en su honor, aunque él no fue su creador. Charles Henry Stanley jugó 3...a6 dos veces en su encuentro de 1845, celebrado en la ciudad natal de Morphy, Nueva Orleans , contra Eugène Rousseau por el Campeonato de Ajedrez de los Estados Unidos . Stanley perdió ambas partidas, aunque ganó el encuentro. ^{[ 18 ]} Howard Staunton también mencionó 3...a6 en su Chess-Player's Handbook , publicado por primera vez en 1847. ^{[ 19 ]} El primer autor en mencionar la jugada fue Ercole del Rio , en su tratado de 1750 Sopra il giuoco degli Scacchi, Osservazioni pratiche dell'anonimo Modenese (Sobre el juego de ajedrez, observaciones prácticas de un anónimo Modenese). ^{[ 20 ]} El campeón mundial de finales del siglo XIX, Wilhelm Steinitz, no aprobó la jugada, escribiendo en The Modern Chess Instructor (1889) que hace avanzar al alfil a una casilla mejor. ^{[ 21 ]} Sin embargo, la opinión de Steinitz no prevaleció; 3...a6 se juega en aproximadamente dos tercios de todas las partidas que comienzan con la Apertura Española (Ruy López). ^{[ 22 ]}

El objetivo de 3...a6 es obligar a las blancas a retroceder o cambiar el alfil por el caballo negro. Así, la jugada "pone la cuestión" ^{[ 13 ]} al alfil, un uso tradicional atribuido a Aron Nimzowitsch . ^{[ 23 ] [ 24 ]} Las blancas deben decidir entre cambiar el alfil por el caballo con 4.Bxc6, la Variante del Cambio , o la retirada más común 4.Ba4. Si 4.Ba4, las negras tendrán la posibilidad de romper una futura clavada en el caballo de dama jugando ...b5.

Tras 4.Ba4, la respuesta habitual de las negras es 4...Nf6, que fue la elección de Morphy en sus partidas con 3...a6. Las alternativas para el cuarto movimiento de las negras incluyen:

• 4...d6 ( Defensa moderna de Steinitz )
• 4...Bc5 ( Defensa Cordel diferida )
• 4...Nge7 ( Defensa de Cozio aplazada )
• 4...g6 ( Defensa de Fianchetto aplazada )
• 4...f5 ( Gambito Jaenisch diferido )
• 4...b5 5.Bb3 Na5 ( Defensa noruega )

Tras 4...Cf6, las negras parecen amenazar el peón e de las blancas. 5.0-0 es, con diferencia, la jugada más común de las blancas, a pesar de dejar el peón desprotegido, ya que eventualmente pueden recuperarlo si juegan 5...Cxe4. Las alternativas para la quinta jugada de las blancas incluyen:

• 5.d3 ( Variante Anderssen )
• 5.Bxc6 ( Variante de Bayreuth )
• 5.Qe2 ( Variante Wormald )
• 5.Cc3 ( Variante Tarrasch )
• 5.d4 ( Variante Mackenzie )

Tras 5.0-0, las negras se enfrentan a una decisión crucial. La continuación más común es la sólida 5...Be7, la Defensa Cerrada, mientras que 5...Nxe4, la Defensa Abierta, y 5...b5, la Defensa Arkhangelsk, representan sistemas alternativos importantes.

• 5...Be7 ( Defensa cerrada )
• 5...Nxe4 ( Defensa Abierta )
• 5...b5 ( Defensa de Arkhangelsk )
• 5...Bc5 ( Defensa Møller )
• 5...d6 ( Defensa rusa )

6.Re1 b5 7.Bb3 d6 8.c3 0-0 9.h3 es la línea principal tradicional de la Defensa Cerrada. A menudo se la considera la línea principal de la Apertura Española en su conjunto, aunque 7...0-0 ahora la rivaliza en popularidad. Miles de partidas de alto nivel han llegado a esta posición. Con 8.c3, las blancas preparan la ruptura central d4 y planean la típica maniobra del caballo Nbd2–f1–g3, reforzando firmemente e4 mientras activan los alfiles en diagonales abiertas y dirigen ambos caballos hacia el flanco de rey de las negras. Las negras, a su vez, buscan contrarrestar este plan expandiéndose en el flanco de dama, desafiando el centro o aumentando la presión sobre e4.

Las negras tienen varias jugadas comunes, incluyendo 9...Na5 ( Variante Chigorin ), 9...Nb8 ( Variante Breyer ), 9...Bb7 ( Variante Zaitsev ), 9...Nd7 ( Variante Karpov ), 9...Be6 ( Variante Kholmov ) y 9...h6 ( Variante Smyslov ). Durante décadas, la Variante Chigorin fue la principal opción de las negras, pero líneas alternativas cobraron protagonismo en la segunda mitad del siglo XX, cuando jugadores como Boris Spassky y Anatoly Karpov buscaron maneras de evitar la necesidad de reposicionar el caballo negro, que se encontraba en una posición incómoda.

Una de las alternativas más agresivas de las negras, el Ataque Marshall es un gambito , ya que 8...d5 sacrifica un peón. El gambito se hizo famoso cuando Frank James Marshall lo utilizó como variante preparada ^{[ 36 ]} contra José Raúl Capablanca en 1918; sin embargo, Capablanca encontró la manera de superar las complicaciones y ganó. ^{[ 35 ] [ 37 ]} El Marshall ha sido adoptado por jugadores de élite como Boris Spassky , John Nunn y Michael Adams . En el Campeonato Mundial de Ajedrez Clásico de 2004 , el aspirante Peter Leko lo utilizó para ganar una partida importante contra el Campeón Mundial Vladimir Kramnik . ^{[ 38 ]} Actualmente, el gran maestro armenio Levon Aronian es uno de los principales defensores del Ataque Marshall. ^{[ 39 ]}

La línea principal del Ataque Marshall comienza con 9.exd5 Nxd5 10.Nxe5 Nxe5 11.Rxe5 c6 (los movimientos originales de Marshall, 11...Nf6 y 11...Bb7, también son jugables). Para el observador casual, podría parecer que las negras han sido descuidadas y han perdido un peón, pero el sacrificio también ha despojado a las blancas de sus defensores del flanco de rey, ha dado a las negras una ventaja en el desarrollo y ha vuelto irrelevante el 8.c3 de las blancas. Generalmente, las negras se lanzan con todo con un ataque masivo en el flanco de rey, que ha sido analizado en profundidad (a veces más allá del movimiento 30) sin llegar a una conclusión definitiva sobre la solidez del Ataque Marshall.

La Defensa Marshall es un sistema de apertura agudo en el que un gran conocimiento teórico es vital, y muchos jugadores de blancas, incluido Garry Kasparov , la evitan jugando uno de los sistemas anti-Marshall. ^{[ 40 ] [ 41 ]} En estas líneas, intentar jugar de forma similar a la Marshall con 8...d5 permite que el caballo blanco en b1 se desarrolle finalmente a c3, mientras que en la Marshall se ve bloqueado por el propio peón blanco. También hay varias alternativas notables a la línea principal de la Marshall. Por ejemplo, las negras pueden jugar 9...e4 en lugar de 9...Nxd5, conocida como la Variante Steiner, ^{[ 42 ]} llamada así en honor al ajedrecista estadounidense Herman Steiner . Las blancas también pueden jugar 9.d4 en lugar de 9.exd5.

A pesar de la naturaleza aguda y táctica del Marshall, ha adquirido reputación como arma de atracción , ^{[ 43 ]} porque un extenso análisis teórico ha trazado muchas líneas de forzamiento que conducen a posiciones equilibradas o jaque perpetuo .

Al jugar 6.d3, a menudo llamada Variante Martínez, ^{[ 45 ]} las blancas evitan el Ataque Marshall y cualquiera de las líneas Anti-Marshall . 6.d3 ha ganado popularidad entre los mejores jugadores y se ha convertido en una alternativa frecuente a la línea principal de la Defensa Cerrada con 6.Re1. Las blancas amenazan 7.Bxc6 para ganar el peón e, dejando a las negras la opción de 6...d6 o 6...b5. La línea más común es 6...b5 7.Bb3 d6, después de lo cual las blancas deben abordar la amenaza de 8...Na5, generalmente con 8.a3, 8.a4 o 8.c3. La variante puede transponerse a líneas 6.Re1 con la ventaja de evitar el Marshall.

Después de 9.c3, las negras tienen la opción entre el tradicional 9...Be7 y el más agresivo 9...Bc5, donde el movimiento más común de las blancas es 10.Nbd2, que casi siempre continúa 10...0-0 11.Bc2. Las negras deben responder al ataque en e4. 11...f5 y 11...Bf5 buscan mantener el punto fuerte en e4, o las negras pueden jugar la línea forzada 11...Nxf2, introducida por el aficionado inglés Vernon Dilworth.

Este movimiento busca limitar las opciones de las negras y es el preferido de Anatoly Karpov . El siguiente movimiento habitual de las negras es 9...Cc5, a lo que las blancas casi siempre responden con 10.c3. Las negras pueden entonces responder con 10...Ae7, una línea que también se suele alcanzar desde la Variante Clásica tras 9.c3 Ae7 10.Cc5 Ae7, o 10...d4. Las negras también pueden optar por jugar 9...Ae7 y luego 10...0-0 (o transponer con 10...Cc5).

En el encuentro del Campeonato Mundial de Ajedrez Karpov- Korchnoi de 1978 , tras 9.Nbd2 Nc5 10.c3 d4, Karpov introdujo la sorprendente 11.Ng5 !? , una jugada sugerida por su entrenador, Igor Zaitsev . ^{[ 55 ]} Si las negras capturan el caballo con 11...Qxg5, las blancas recuperan el material con 12.Qf3. Esta variante jugó un papel decisivo en un posterior encuentro del Campeonato Mundial, Kasparov - Anand 1995, cuando Anand no pudo defenderse con éxito jugando con negras. ^{[ 56 ]}

En el Ataque Howell ( ECO C81), las blancas buscan jugar contra d5 después de Rd1. La partida suele continuar con 9...Be7 10.Rd1 seguido de 10...Nc5 o 10...0-0. Paul Keres jugó esta línea contra Max Euwe y Samuel Reshevsky en el Campeonato Mundial de Ajedrez de 1948. [ ^{57 ] [ 58 ] Esta} línea ha sido jugada al más alto nivel por el número 2 del mundo, Fabiano Caruana, entre otros, y la recomienda en su serie de videos para Chessbase.

Esta variante se considera inferior. La línea principal va 7.Re1 d5 8.Nxd4 Bd6! 9.Nxc6 Bxh2+! 10.Kh1! Qh4 11.Rxe4+! dxe4 12.Qd8+! Qxd8 13.Nxd8+ Kxd8 14.Kxh2 Be6 (14...f5 ?? 15.Bg5 # ) y ahora el final se considera que favorece a las blancas después de 15.Be3 o Nd2 (pero no 15.Nc3 c5!, jugando para atrapar al alfil). Un ejemplo famoso de esta línea es la partida José Raúl Capablanca – Edward Lasker , Nueva York 1915. ^{[ 59 ]} Las blancas son objetivamente mejores aquí, pero las negras mantienen algunas buenas posibilidades prácticas debido a las posiciones agudas que se producen.

Las blancas deben tener cuidado de jugar 10.Kh1 en la línea principal en lugar del intuitivo 10.Kxh2, porque después de 10.Kxh2 Qh4+ 11.Kg1 Qxf2+, las negras pueden forzar un empate por jaque perpetuo .

Las blancas también tienen las notables alternativas para el octavo movimiento: 8.Bg5, la Variante Berger, y 8.c4.

• En la línea principal 6.d4 b5 7.Bb3 d5 8.dxe5 Be6, 9.Be3 se usa a menudo para transponer a la línea principal con 9.c3 Be7, eliminando la opción de 9.c3 Bc5.
• Después de 6.d4 b5 7.Bb3, 7...exd4 es débil debido a 8.Re1 d5 9.Nc3!, visto en Bobby Fischer – Petar Trifunović , Bled 1961. ^{[ 60 ]}
• 6.d4 b5 7.Bb3 d5 8.Nxe5, que en su día adoptó Fischer, también es jugable. Las negras deberían igualar tras la precisa 8...Nxe5 9.dxe5 c6, que evita comprometer prematuramente el alfil de casillas blancas y defiende sólidamente d5, un problema frecuente en el Abierto.
• 6.d4 b5 7.Nxe5 es el Ataque Friess, poco común. Generalmente continúa con 7...Nxe5 8.dxe5, y desde ahí se puede jugar 8...Nc5 9.Bb3 Nxb3 10.axb3 Bb7 o 8...d5 9.Bb3, transponiendo a la línea de Fischer mencionada anteriormente. También es posible 7...bxa4, con las blancas planeando Qe2 y Nxc6.
• 6.d4 b5 7.d5 es la Variante Richter. Generalmente continúa con 7...bxa4 (o 7...Ne7 8.Re1) 8.dxc6 d6 9.c4 Be7. Las blancas pueden recuperar el peón con 10.Qxa4, pero esta línea no es bien vista.
• 6.d4 Be7 suele continuar 7.Re1 b5 8.Rxe4 d5 9.Nxe5 Nxe5 10.Rxe5 bxa4. Las negras pueden verse obligadas a retrasar el enroque después de 11.Qe2 debido a la presión sobre el alfil negro en e7, con las respuestas habituales 11...Be6, 11...c6 y 11...f6. La línea también puede alcanzarse a través de 6.d4 b5 7.Bb3 Be7. Las negras no pueden jugar 9...dxe4 debido a 10.Nxc6, lo que obliga a las negras a mover la dama, seguido de 11.Nxe7.
• 6.Re1 es la principal alternativa de las blancas para el sexto movimiento. Lo más frecuente es que continúe 6...Cc5 7.Axc6 dxc6 8.Cxe5 Ae7 9.d4 Ce6 10.Ae3 0-0, y desde ahí a menudo 11.c4 f6 12.Cf3; 8.d4 Ce6 9.Cxe5 Ae7 transpone a la misma línea.

Esta línea suele conducir a posiciones agudas en las que las negras apuestan a que la influencia del alfil en fianchetto sobre el centro y el flanco de rey compensará su retraso en el enroque. Tácticamente se justifica por la capacidad de las negras para responder a 7.Ng5 con 7...d5 8.exd5 Nd4! (no 8...Nxd5, cuando las blancas obtienen ventaja con 9.Qh5 g6 10.Qf3). Las blancas tienen varias opciones, incluyendo intentar construir un centro de peones ideal con los inmediatos 7.c3 y 8.d4, defender el peón de e con 7.Re1, o simplemente desarrollar con 7.d3.

La Defensa Arkhangelsk Moderna (o Defensa Arcángel Moderna), a veces llamada Neo-Arkhangelsk o Neo-Arcángel, es un refinamiento de la Defensa Arkhangelsk regular al incorporar ideas similares a la Defensa Møller (5...Bc5). La línea tradicional continúa 7.c3 d6 8.d4 (8.a4 Rb8 transpone a la línea principal moderna 7.a4) 8...Bb6 y la posición de las negras es buena. Una justificación clave de la línea es que después de 9.dxe5 Nxe5 10.Nxe5 dxe5 11.Qxd8+ Kxd8 12.Bxf7 las blancas parecen ganar un peón, pero después de 12...Rf8 13.Bd5 Nxd5 14.exd5 Bb7 las negras recuperan el peón con una posición igualada (si 13.Bb3 Nxe4 14.Bd5? intenta atacar las dos piezas, 14...Nxf2! gana para las negras con un ataque devastador). ^{[ 61 ]}

The Modern Arkhangelsk started to gain popularity in the 1990s (due significantly to the efforts of Alexei Shirov) when the main continuation 7.a4 Rb8 8.c3 d6 9.d4 Bb6 was established (7...Bb7 is also possible, leading to positions similar to the traditional Arkhangelsk). A typical idea is to play ...Bg4 to increase the pressure against White's pawn centre. Critical modern tries for White include targeting the b5 pawn with 10.Na3, leading to sharp positions where Black often sacrifices that pawn, or 10.a5, gaining space on the queenside and where the pawn is known to be tactically immune from capture.^[62][63]Fabiano Caruana is one of the most notable recent exponents of this variation, employing it in the Candidates Tournament 2020.^[64][65]

• 6...Be7 usually continues with 7.Re1, transposing to the main line of the Closed Defence. White can also opt to play 7.d4, usually continuing 7...d6 and then 8.c3 0-0 (or 8...Bg4), with transposition to the main line possible if White later plays Re1, or 8.dxe5, which usually leads to an endgame after 8...dxe5 9.Qxd8+ Kxd8 or 8...Nxe5 9.Nxe5 dxe5 10.Qxd8+ Kxd8. 7.d3 and 7.a4 are also possible alternatives for White.
• 6...d6 usually continues with 7.Re1 or 7.c3, both most often transposing to the main line after 7...Be7, though in the latter case White can avoid the transposition by not playing Re1. 7.a4 and 7.Ng5 are also possible.
• 6...Nxe4 usually transposes to the Open Defence after 7.d4, but an independent line with 7.Re1 is also possible. Its usual continuations are 7...d5 8.Nc3 Nxc3 9.dxc3 Be6 10.a4 and 7...Nc5 8.Bd5.

The Russian Defence (ECO C79) is also called the Steinitz Defence Deferred. With the move order 3...a6 4.Ba4 Nf6 5.0-0 d6, Black waits until White castles before playing ...d6. This can enable Black to avoid some lines in the Modern Steinitz Defence (4...d6) in which White castles queenside, although the position of the knight on f6 also precludes Black from supporting the centre with ...f7–f6.

Mikhail Chigorin played the Russian Defence in the 1890s, and later it was adopted by Akiba Rubinstein and Alekhine. The last significant use of the Russian Defence was in the 1950s, when it was played by some Russian masters. Today, however, it has purely practical value, as White has found numerous ways to gain an opening advantage by quickly opening lines in the centre, where Black's developmental lag seems to be a significant factor.

5...Bc5 is the Møller Defence. The usual continuation is 6.c3 b5, after which White can either play 7.Bb3, transposing to the Modern Arkhangelsk Variation, or 7.Bc2. 6...0-0 is also seen, usually continuing 7.d4 Ba7. White also has the options of 7.d3, 7.Bxc6, and 7.Nxe5, aiming to fork Black's knight and bishop after 7...Nxe5 8.d4.

The Møller Defence is named after Jørgen Møller (1873–1944), who analysed it in Tidskrift för Schack.^[66]Alexander Alekhine played it with Black in the early portion of his career; despite his advocacy, it never achieved great popularity, and even he eventually came to consider it dubious.

5.d3 is the most popular alternative to 5.0-0. It defends White's e-pawn and indirectly threatens Black's e-pawn with Bxc6 followed by Nxe5, since ...Qd4 no longer targets an undefended pawn. Black can meet this idea with 5...b5, 5...d6, or 5...Bc5, intending to answer Bxc6 and Nxe5 with ...Qd4, attacking the knight on e5 while simultaneously creating a queen–bishop battery against f2.

After 5...b5 6.Bb3, Black usually plays 6...Bc5, developing the bishop to a much more active square compared to 6...Be7, which, after 7.0-0, would transpose to the Martinez Variation.

With 5...d6, Black intends to trade White's bishop following 6...b5 7.Bb3 Na5. White can choose to meet this idea with 6.c3, which, after 6...Be7, transposes into the Martinez Variation, or play 6.c4 (Duras Variation), aiming to stop b7–b5 and develop actively with h3, 0-0, Nc3.

Against 5...Bc5, play typically continues 6.c3 b5 7.Bb3 d6 8.0-0 0-0. At this point, White often adopts the more thematic plans 9.Nbd2 or 9.h3; however, the strongest continuation is 9.Bg5. After 9...h6 10.Bh4 g5 White must choose between the safer 11.Bg3 or the sharper 11.Nxg5.

If White wants to play a Ruy Lopez with d2–d3, it is objectively slightly better to first play 5.0-0, wait for Black to play 5...Be7, then play the Martinez (6.d3). This is because in the Anderssen, it is not clear if White has an advantage after 5...Bc5. On the other hand, 5.d3 avoids the Open Defence.

5.d4 has been called the Mackenzie Variation, after George Henry Mackenzie, who employed it on a regular basis. It has also been called the Centre Attack.^[67] It is an old line which, according to modern theory, does not promise White any advantage, though it is still occasionally used and leads to sharp play. The main continuation is 5...exd4 6.0-0 Be7, a position also frequently reached from the Closed Defence after 5.0-0 Be7 6.d4 exd4.^[47]

A frequently played line is 7.Re1 b5 8.Bb3 d6 9.Bd5 Nxd5 10.exd5 Ne5 11.Nxd4 0-0. 7...0-0 is also playable for Black; White's response 8.e5 kicks Black's knight, which must relocate with 8...Ne8 or 8...Nd5.

7.Re1 b5 8.e5 is a sharp line typically met with 8...Nxe5. White can respond with 9.Rxe5, where two common lines are 9...d6 10.Re1 bxa4 11.Nxd4 Bd7 12.Qf3 0-0 13.Nc6 Bxc6 14.Qxc6, where White can later play Qxa4 to equalize material, and 9...bxa4 10.Nxd4 0-0 11.Nf5 Re8 12.Bg5 d6 13.Nxe7+ Rxe7 14.Bxf6 gxf6, which leaves Black up a pawn but with an exposed king. A common alternative to 9.Rxe5 is 9.Nxe5, which most often continues 9...bxa4 10.Qxd4 0-0 11.Qxa4 Rb8 (or 11.Nc3 or 11.Bg5).

In case of the immediate 7.e5, Black can take advantage of the absence of White rook from e1 by playing 7...Ne4, a position also reachable via 6.e5 Ne4 7.0-0 Be7. The line is considered harmless because the usual 8.Nxd4 can be met with 8...0-0, where the aggressive 9.Nf5 can be countered with 9...d5;^[67] the knight will be exchanged after 10.Nxe7+ Qxe7, 10.Bxc6 bxc6 11.Nxe7+ Qxe7, or 10.exd6 Bxf5. 8...Nxd4 9.Qxd4 Nc5 is a common alternative line; a possible continuation is 10.Nc3 0-0 11.Nd5, where an endgame can be reached after 11...d6 12.Nxe7+ Qxe7 13.exd6 Qxd6 14.Qxd6 15.Bb3 Nxb3 16.axb3. 8...Nc5 is also seen for Black, as are 8.Re1 and 9.Re1 for White.

There are some rare early deviations. For Black, 6...b5 and 6...d6 are playable, and 6...Nxe4 transposes to the Riga Variation. 6...Bc5 is weak due to 7.e5, as 7...Ne4, paralleling the 6...Be7 7.e5 line, is well met by 8.Re1. 6.e5 was tried by Mackenzie as an alternative to 6.0-0; it can be met with 6...Nxe4. 7.0-0 Be7 then transposes to the 7.e5 line, but Black can instead play 7...Nc5. On the fifth move, Black can also attempt to transpose to the Open Defence with 5...Nxe4. White can accept this with 6.0-0 or decline by playing 6.Qe2 instead.

5.Qe2, first played in the 1840s, normally continues 5...b5 6.Bb3 Be7 7.c3 followed by 8.d4. Robert Wormald (1834–1876) wrote openings manuals and completed Staunton's last book, analysing the line in Chess World, 1867. The line is also known as Paulsen–Alapin Attack, and Schlechter Variation.^[68] Transposition to the Worrall Attack is also common via 7.0-0 or 8.0-0; Black can avoid this by playing 6...Bc5 instead of 6...Be7.

5.Nc3 is the Tarrasch Variation, also known as the Four Knights Variation. It can also be reached by transposition from the Four Knights Game after 3.Nc3 Nf6 4.Bb4 a6 5.Ba4, although this is rare. A common line is 5...b5 6.Bb3 and then 6...Be7 or 6...Bc5. White may try to take the initiative with 7.d3 d6 8.Nd5, or alternatively 7.0-0 d6 8.Nd5, where 8...Nxe4 can be met with 9.d4 and 10.Re1.^[67] Transposition to the Morphy Attack and other lines is common.

5.Bxc6 is the Bayreuth Variation, also known as the Delayed Exchange Variation or Exchange Variation Deferred. White loses a tempo compared to the standard Exchange Variation, but Black can no longer easily play ...f6 or ...Qf6, common moves in that line. Similarly to the Steenwijk Variation, after 5...dxc6, 6.d3 is the main move, but unlike in the Steenwijk, Black can play 6...Bd6 without losing tempo.

4...d6 (ECO C71–C76) is the most common fourth move sideline for Black and has been called the Modern Steinitz Defence, Deferred Steinitz Defence,^[69] and Neo-Steinitz Defence.^[70] It was frequently played by Alexander Alekhine, José Raúl Capablanca, and Paul Keres. The ability to break the pin with a timely ...b5 gives Black more flexibility than in the regular Steinitz Defence (3...d6). Notably, in the regular Steinitz Defence, White can almost always force Black to surrender the stronghold at e5. In the Modern Steinitz Defence, however, Black retains control of the centre. White's most plausible moves are playable here, including 5.c3, 5.c4, 5.Bxc6, 5.d4, and 5.0-0.

If White plays 5.d4, analogous to the Steinitz Defence, Black can immediately break the pin with 4...b5. After 5.Bb3 Nxd4 6.Nxd4 exd4, the natural 8.Qxd4 is in fact a mistake, as it falls into Noah's Ark Trap.^[71] In the game Steiner–Capablanca, Budapest 1929, play continued 8...c5 9.Qd5 Be6 10.Qc6+ Bd7 11.Qd5 c4 when White's bishop is trapped.^[72]

The sharp Siesta Variation arises after 5.c3 f5,^[73] while a manoeuvring game results from the calmer 5.c3 Bd7 6.d4. The game is also sharp after 5.Bxc6+ bxc6 6.d4 (C73) or 5.0-0 Bg4 6.h3 h5 (C72). The older lines starting with 5.c4 and 5.d4 are not regarded as testing for Black, though the latter offers a tricky gambit.

There are six ECO classifications for the Modern Steinitz. White's responses 5.d4, 5.Nc3, and 5.c4 are included in C71, while 5.0-0 is C72. The delayed exchange 5.Bxc6+ bxc6 6.d4 is C73. C74–C76 all begin with 5.c3. C74 covers 5...Nf6, but primarily focuses on 5...f5 6.exf5 Bxf5 with 7.d4 or 7.0-0. C75's main continuation is 5...Bd7 6.d4 Nge7, the Rubinstein Variation. C76 is characterised by the Black kingsidefianchetto 5...Bd7 6.d4 g6.

The Norwegian Defence (also called the Taimanov Variation^[74] or Wing Variation) (ECO C70), 3...a6 4.Ba4 b5 5.Bb3 Na5, aims to eliminate White's bishop but is generally considered too time-consuming for Black. The usual continuation is 6.0-0 d6 7.d4 Nxb3, but the speculative sacrifice 6.Bxf7+?! Kxf7 7.Nxe5+ Ke7!, which drives the black king out, has been played. With accurate play, however, Black can avoid any disadvantage while holding onto the extra piece, unless White opts to gain a rook and two pawns for two minor pieces after 8.Nf7!? Kxf7 9.Qh5+ g6 (9...Ke7 10.Qe5+) 10.Qd5+ Kg7 11.Qxa8, with a sharp position but advantage for Black.

In the 1950s, Mark Taimanov played it with some success, though it remained a sideline, as it has to this day. This defence has been known since the 1880s and was reintroduced in 1901 by Carl Schlechter. The Norwegian connection was first introduced by Svein Johannessen who played the line from 1957 and later strengthened when Simen Agdestein and some other Norwegian players adopted the variation. In 1995 Jonathan Tisdall published the article "Ruy Lopez. The Norwegian Variation" in New in ChessYearbook 37.

The Cordel Defence Deferred combines 3...a6 with the active move ...Bc5. For a century it was believed that it was safer for Black to place the bishop on e7, but it is much more active on c5. White can gain time by playing c3 and d4 as Black's bishop will have to move, but this does not always seem to be as important as was once thought.^[75] White also has the option of 5.0-0, which can transpose to the Graz Defence after 5...b5 6.Bb3, but more common are 5...Nge7 and 5...d6.

4...Nge7 is the Cozio Defence Deferred. Unlike many other deferred versions of other lines, it is frequently reached by transposition from the standard Cozio Defence (3...Nge7).

It has been advocated by Levon Aronian, and in recent years additional elite players, such as Fabiano Caruana, Dommaraju Gukesh, and Rameshbabu Praggnanandhaa have also begun experimenting with 3...a6 4.Ba4 Nge7. The critical line continues 5.c3 Ng6 6.d4 exd4 7.cxd4 Bb4+ 8.Nc3 d5 9.exd5 Bxc3+ 10.bxc3 Qxd5 11.0-0 0-0, after which White retains the bishop pair, while Black has the better pawn structure.

The Jaenisch Gambit Deferred or Jaenisch-Schliemann Gambit Deferred, 3...a6 4.Ba4 f5, is rarely seen, with practically its only top-level appearances being in the 1974 Candidates Final, when Viktor Korchnoi adopted it to ultimately draw the game versus Anatoly Karpov,^[76] and by Rameshbabu Praggnanandhaa who won against Vidit Gujrathi in the 2024 Candidates Tournament.^[77] It is considered inferior to the regular Jaenisch Gambit since White can respond effectively with 5.d4!, and now both 5...exd4 6.e5 and 5...fxe4 6.Nxe5 Nxe5 7.dxe5 lead to a White advantage.

• After 4...b5 5.Bb3, alternatives to the Norwegian Defence (5...Na5) include 5...Nf6, attempting to transpose to the main line but allowing White the option of 6.d4; 5...Bb7, the Caro Defence, usually transposing to the Arkhangelsk Variation after 5.0-0 Nf6, but also allowing 6.d4; and 5...Bc5, known as the Graz Defence, usually continuing with 5.0-0 or 5.c3, which was analysed by Alois Fink in Österreichische Schachzeitung in 1956 and in Wiener Schach Nachrichten in 1979, although it did not become popular until the 1990s.
• 4...g6 is the Fianchetto Defence Deferred. Like the Cozio Defence Deferred, it is also often reached by transposition from the standard Fianchetto Defence (3...g6), such as via 4.c3 a6 5.Ba4.
• 4...Be7 usually transposes to the main line after 5.0-0 Nf6.

The Berlin Defence (ECO C65-C67), 3...Nf6,^[83] is by far Black's most common third move alternative. It has long had a reputation for solidity and drawishness. The line was common in the late 19th century and early 20th century, being played by Emanuel Lasker and others, though it declined in popularity afterward. After Vladimir Kramnik successfully used the line as a drawing weapon four separate times against Garry Kasparov in their 2000 World Chess Championship match, however, the Berlin experienced a remarkable renaissance. Even players with a dynamic style such as Alexei Shirov, Veselin Topalov, Hikaru Nakamura, and Kasparov himself have tried it, and Magnus Carlsen and Viswanathan Anand both used it (Carlsen extensively so) during the 2013 World Chess Championship and 2014 World Chess Championship. White usually responds with 4.0-0 or 4.d3.

The Jaenisch Gambit, Jaenisch–Schliemann Gambit, or Schliemann Defence (ECO C63), 3...f5,^[73] is a sharp line in which Black plays for a kingside attack, frequently sacrificing one or two pawns. The variation was originated by Carl Jaenisch, who analysed it in the December 1847 issue of Le Palamède.^[91] Although later named for German lawyer Adolph Schliemann (1817–1872) in the Handbuch des Schachspiels,^[92], the line Schliemann actually advocated for in the 1860s was a gambit variation of the Cordel Defence (3...Bc5 4.c3 f5).^[93]

The Jaenisch Gambit is considered to be a good practical weapon, but is positionally risky, especially against a strong and prepared opponent. Teimour Radjabov is currently the only top player who regularly employs this line, with mixed results.

The most common responses for White to 3...f5 are 4.d3 or 4.Nc3, with play after 4.Nc3 fxe4 5.Nxe4 going 5...d5, leading to the most heavily analysed variations of the gambit,^[94] with great complications to follow, or 5...Nf6, which generally leads to quieter play. 4.exf5?! is inferior; after 4...e4 5.Qe2 Qe7 6.Bxc6 dxc6 7.Nd4 Nh6 Black has the better of it.^[95]

The Cordel Defence,^[96] also known as the Classical Defence (ECO C64), 3...Bc5,^[89] is possibly the oldest defence to the Ruy Lopez, and has been played occasionally by former world championBoris Spassky and Boris Gulko. It is uncommon today, however, and was never particularly common, as White will be able to kick the bishop after c3 and d4.^[97] White's most common reply is 4.c3, but 4.0-0 is a close second, and 4.Nxe5 and 4.d3 are also seen.

After 4.c3, Black may choose to play 4...f5, the Cordel Gambit, leading to sharp play, after which 5.d4 is considered the strongest reply. The main line of the gambit continues 5...fxe4 6.Bxc6 dxc6 7.Nxe5 Bd6 8.Qh5+ g6 9.Qe2. More solid for Black is 4...Nf6;^[96] the usual 5.0-0 transposes to a line of the Beverwijk Variation of the Berlin Defence. 4...Nge7 (typically transposing to the 4.0-0 Nge7 line below), 4...Qf6, and 4...Bb6 are also played. 4...d6 is weak to 5.d4.

White's principal alternative to 4.c3 is 4.0-0. Black can again transpose to the Beverwijk with 4...Nf6, but the most common reply for Black is 4...Nd4. It is a more positional variation; a typical line is 5.Nxd4 Bxd4 6.c3 Bb6 7.d4 c6, followed by 8...d6.^[96] Also common for Black are 4...Nge7, which has the main line 5.c3 Bb6 6.d4 exd4 7.cxd4 d5 8.exd5 Nxd5 9.Re1+ Be6 10.Bg5 Qd6 (10...f6 hangs the bishop) 11.Nbd2 0-0 12.Nc4 Qb4, as well as 4...Qf6 and 4...d6,^[98] but 4...f5 can be met with 5.exf5 e4 6.Re1.^[96]

The fork trick 4.Nxe5 is possible. The name derives from White's play if Black captures the knight: 4...Nxe5 5.d4. Few games have been played with this line, but there is no clear refutation for Black, though 4...Qe7 and 4...Qg5 are strong alternatives to 4...Nxe5.

The Fianchetto Defence, also known as the Smyslov Defence, Barnes Defence, or Pillsbury Defence (part of ECO C60), 3...g6, is a quiet positional system played occasionally by Vasily Smyslov and Boris Spassky,^[99] becoming popular in the 1980s when it was shown that 4.c3 a6! gives Black a good game.

It was later discovered that 4.d4 exd4 5.Bg5 gives White the advantage, and as such the variation is rarely played. An interesting gambit line 4.d4 exd4 5.c3 has also been recommended by Alexander Khalifman, although some of the resulting positions have yet to be extensively tested.

The Cozio Defence (part of ECO C60), 3...Nge7, is a distinctly old-fashioned uncommon choice for Black's third move. Although Bent Larsen used it occasionally with success, it remains one of the least explored variations of the Ruy Lopez. The Cozio Defence seeks to avoid doubled pawns on the c-file, as if White captures Black's knight on c6, Black may recapture with Nxc6.

Bird's Defence (ECO C61), 3...Nd4,^[89] is an uncommon variation in modern praxis. With careful play White is held to gain an advantage. The best moves are 4.Nxd4 exd4 5.0-0 Bc5 6.d3 c6 7.Ba4 Ne7.

This defence was published in 1843 in Paul Rudolf von Bilguer's Handbuch des Schachspiels and explored by Henry Bird in the late 19th century. Bird played it as Black at least 25 times, scoring +9−13=3 (nine wins, thirteen losses, three draws).^[100] Bird's Defence was later used a few times in tournament play by Siegbert Tarrasch, Boris Spassky, and Alexander Khalifman. Although it is still sometimes seen as a surprise weapon, no strong master since Bird has adopted it regularly.^[101] The world champion Magnus Carlsen played it as Black in the 2014 Chess Olympiad against Ivan Šarić and lost.^[102]

The Steinitz Defence (also called the Old Steinitz Defence) (ECO C62), 3...d6, is solid but passive and cramped. Although the favourite of the first world championWilhelm Steinitz, and often played by world champions and expert defensive players Emanuel Lasker, José Raúl Capablanca, and occasionally by Vasily Smyslov, it largely fell into disuse after World War I, as its inherent passivity spurred a search for more active means of defending the Spanish.

White's most direct approach is 4.d4 immediately challenging Black's pawn on e5, while 4.c3 and 4.0-0 remain viable alternatives. Following 4.d4, Black proceeds with 4...Bd7 which breaks the pin but also defends against White's threat of winning a pawn with 5.Bxc6 and 6.dxe5. Next White plays 5.Nc3 protecting e4 and renewing the threat of winning a pawn to which Black responds with 5...Nf6. After 6.0-0 Be7 7.Re1 Black is forced to concede the centre with 7...exd4, since 7...0-0? leads to the Tarrasch Trap.

The Modern Steinitz Defence (3...a6 4.Ba4 d6) offers Black a freer position and is more popular.

Even less common third moves for Black include:

• 3...Bb4 (Alapin Defence)
• 3...Qf6 (Frankfurt Defence)^[103]
• 3...f6 (Nuremberg Variation)^[104]
• 3...Qe7 (Vinogradov Variation)
• 3...Na5 (Pollock's Defence)
• 3...g5 (Brentano Defence)^[105]
• 3...b6 (Rotary Defence or Albany Defence)
• 3...d5 (Sawyer's Gambit or Spanish Countergambit)
• 3...Be7 (Lucena Defence)
• 3...a5 (Bulgarian Variation)