Editing King's Gambit (section)

== King's Gambit Accepted: 2...exf4 <span id="King's Gambit Accepted"></span> ==
Although Black usually accepts the gambit pawn, two methods of declining the gambit—the [[#Classical Defense|Classical Defense]] (2...Bc5) and the [[#Falkbeer Countergambit|Falkbeer Countergambit]] (2...d5)—are also popular. After [[b:Chess Opening Theory/1. e4/1...e5/2. f4/2...exf4|2...exf4]], the two main continuations for White are 3.Nf3 (King's Knight's Gambit) and 3.Bc4 (Bishop's Gambit).

=== King's Knight's Gambit: 3.Nf3 <span id="King's Knight's Gambit"></span> ===
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| King's Knight's Gambit: 3.Nf3 
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This is the most popular move. It develops the [[knight (chess)|knight]] and prevents 3...Qh4+. Black's two main approaches are to attempt to hold on to the pawn with ...g5, or to return the pawn in order to facilitate {{chessgloss|development}}.

==== Classical Variation: 3...g5 <span id="Classical Variation"></span> ====
The Classical Variation arises after 3.Nf3 g5. Black defends the f4-pawn, and threatens to kick the f3-knight with ...g4, or else to consolidate with ...Bg7 and ...h6. The main continuations traditionally have been 4.h4 and 4.Bc4. More recently, 4.Nc3 (the Quaade Gambit or Quaade Attack)<ref>For the origin of the term "Quaade Attack" or "Quaade Gambit" see "[http://www.chesshistory.com/winter/extra/gamelet.html A Chess Gamelet]" by [[Edward Winter (chess historian)|Edward Winter]], 2014</ref> has been recommended by Scottish grandmaster (GM) [[John Shaw (chess player)|John Shaw]] as a less explored alternative to 4.h4 and superior to 4.Bc4.<ref>[[John K. Shaw|John Shaw]], ''The King's Gambit'', Quality Chess, 2013, p. 137. {{ISBN|978-1-906552-71-8}}.</ref>

===== 4.h4: Kieseritzky Gambit and Allgaier Gambit <span id="Kieseritzky Gambit and Allgaier Gambit"></span> =====
With 4.h4 White practically forces 4...g4, thereby undermining any attempt by Black to set up a stable pawn chain with ...h6 and ...Bg7.

The [[Kieseritzky Gambit]], 4.h4 g4 5.Ne5, is considered by modern writers such as Shaw and Gallagher to be the main line after 3...g5. It was popularized by [[Lionel Kieseritzky]] in the 1840s and used successfully by [[Wilhelm Steinitz]]. [[Boris Spassky]] used it to beat [[Bobby Fischer]] in a famous game at [[Mar del Plata chess tournament|Mar del Plata]] in 1960.<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1080046 |title=Spassky vs. Fischer, Mar del Plata 1960 |website=[[Chessgames.com]] }}</ref> The main line of the Kieseritzky Gambit is considered to be 5...Nf6 (Berlin Defense) 6.Bc4 d5 7.exd5 Bd6 8.d4 Nh5 9.0-0 Qxh4 10.Qe1 Qxe1 11.Rxe1 0-0 12.Bb3 Bf5. The Long Whip Variation, 5...h5?! 6.Bc4 Rh7 (or 6...Nh6) is considered old-fashioned and risky, as Black loses a lot of time attempting to hold on to the pawn.

4.h4 g4 5.Ng5 is the [[Johann Baptist Allgaier|Allgaier]] Gambit,<ref>{{cite book
 |last1=Kasparov
 |first1=Gary
 |author-link1=Garry Kasparov
 |last2=Keene
 |first2=Raymond
 |author-link2=Raymond Keene
 |title=Batsford Chess Openings
 |publisher=American Chess Promotions
 |year=1982
 |pages=288–89
 |isbn=0-7134-2112-6}}</ref> intending 5...h6 6.Nxf7. This knight sacrifice is considered unsound.<ref>Shaw, pp. 200–202</ref>

===== 4.Bc4 g4: Muzio Gambit and others <span id="Muzio Gambit and others"></span> =====
The extremely {{chessgloss|sharp}} [[Muzio Gambit]]<ref name="muz">For the origins of the name "Muzio" and how the eponymous variation came to be labeled, see [[Giulio Cesare Polerio#Polerio Gambit|Polerio Gambit]]</ref> arises after 4.Bc4 g4 5.0-0 gxf3 6.Qxf3, where White has sacrificed a knight but has three pieces bearing down on f7.<ref>[https://www.youtube.com/watch?v=YfZK_KqKBtY Nakamura vs. Andreikin]</ref> Such wild play is rare in modern chess, but Black must defend accurately. Perhaps the sharpest continuation is the Double Muzio after 6...Qf6 7.e5 Qxe5 8.Bxf7+{{chesspunc|!?}}, leaving White two pieces down in eight moves, but with a position that some masters consider to be equal.<ref name=millican>[http://www.millican.org/chess/muzio.pdf Peter Millican 1989]</ref><ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1074916 |title=Shirov vs. J Lapinski, Daugavpils 1990 |website=[[Chessgames.com]] }}</ref> In practice White's play seems to be easier, especially when the opponent is surprised by such daring tactics.

Similar lines are the [[Ghulam Kassim]] Gambit, 4.Bc4 g4 5.d4, and the [[McDonnell Gambit]], 4.Bc4 g4 5.Nc3. These are generally considered inferior to the Muzio, which has the advantage of reinforcing White's attack along the f-file. Also inferior is the [[Giambattista Lolli|Lolli]] Gambit 4.Bc4 g4 5.Bxf7+{{chesspunc|?!}}, which leaves White with insufficient [[Compensation (chess)|compensation]] for the piece after 5...Kxf7 6.Ne5+ Ke8 7.Qxg4 Nf6 8.Qxf4 d6.

The [[Alessandro Salvio|Salvio]] Gambit, 4.Bc4 g4 5.Ne5 Qh4+ 6.Kf1, is considered better for Black due to the insecurity of White's king. Black may play safely with 6...Nh6 (Silberschmidt Variation), or counter-sacrifice with 6...f3 ([[John Cochrane (chess player)|Cochrane]] Gambit) or 6...Nc6 (Viennese Variation).

===== 4.Bc4 Bg7: Hanstein Gambit and Philidor Gambit <span id="Hanstein Gambit and Philidor Gambit"></span> =====
A safer alternative to 4...g4 is 4...Bg7,<ref name=millican/> which usually leads to the Hanstein Gambit after 5.d4 d6 6.0-0 h6 or the Philidor Gambit after 5.h4 h6 6.d4 d6 (other move orders are possible in both cases).

===== 4.Nc3: Quaade Gambit <span id="Quaade Gambit"></span> =====
The Quaade Gambit (3.Nf3 g5 4.Nc3) is named after a Danish amateur who discussed it in correspondence with the ''[[Deutsche Schachzeitung]]'' in the 1880s.<ref>[[Edward Winter (chess historian)|Edward Winter]], [http://www.chesshistory.com/winter/winter116.html#8589._The_Quaade_Gambit_C.N.s_ ''A Chess Gamelet''], 5 March 2014</ref> The move has received renewed attention following its recommendation by John Shaw in his 2013 book on the King's Gambit. A well-known trap here is 4...g4 5.Ne5 Qh4+ 6.g3 fxg3 7.Qxg4 g2+{{chesspunc|?}} (7...Qxg4 8.Nxg4 d5 is about equal) 8.Qxh4 gxh1=Q 9.Qh5{{chesspunc|!}} and White is close to winning. (Black's best defense is considered 9...Nh6 10.d4 d6 11.Bxh6 dxe5 12.Qxe5+ Be6 13.Qxh8 Nd7 14.Bxf8 0-0-0 and White will emerge a clear pawn ahead.) Instead, 4...Bg7 has been recommended. 4...d6 and 4...h6 transpose to Fischer's Defense and Becker's Defense, respectively. Also possible is 4...Nc6, recommended by [[Konstantin Sakaev]].<ref>Shaw, p. 141</ref><ref>Korchnoi & Zak, pp. 38–39.</ref>

After 4...Bg7 5.d4 g4, [[Simon Williams (chess player)|Simon Williams]] advocates 6.Bxf4 gxf3 in his DVD and [[Chess.com]] video series.<ref>{{Cite web|url=https://en.chessbase.com/post/8-5-out-of-10-with-the-king-s-gambit|title=8.5 out of 10 with the King's Gambit|date=30 June 2014}}</ref> White is down a knight, but has a strong attack. The Quaade Gambit has recently been advocated by [[Daniel King (chess player)|Daniel King]] in his PowerPlay series for Chessbase.

===== 4.d4: Rosentreter Gambit <span id="Rosentreter Gambit"></span> =====
This is likely to lead to similar positions to the Quaade Gambit; however, 4...g4 5.Ne5 Qh4+ 6.g3 fxg3 7.Qxg4 g2+!? (7...Qxg4=) is now viable due to the threat against the pawn on e4. After 8.Qxh4 gxh1=Q Shaw recommends 9.Nc3 for White, with a complicated position.<ref>Shaw, pp. 186–196</ref>

==== Becker Defense: 3...h6 <span id="Becker Defense"></span> ====
The [[Albert Becker (chess player)|Becker]] Defense (3.Nf3 h6), has the idea of creating a {{chessgloss|pawn chain}} on h6, g5, f4 to defend the f4 pawn while avoiding the Kieseritzky Gambit, so Black will not be forced to play ...g4 when White plays to undermine the chain with h4. White has the option of 4.b3, although the main line continues with 4.d4 g5 (''[[Encyclopaedia of Chess Openings|ECO]]'' C37) and usually transposes to lines of the Classical Variation after 5.Bc4 Bg7 6.0-0 (''ECO'' C38).

==== Bonch-Osmolovsky Defense: 3...Ne7 <span id="Bonch-Osmolovsky Defense"></span> ====
The rarely seen Bonch-Osmolovsky Defense<ref>Named after [[USSR|Soviet]] national master Mikhail Aleksandrovich Bonch-Osmolovsky (1919–1975), also chess theorist and arbiter. See [http://www.chessgames.com/perl/chessplayer?pid=32305 Mikhail Aleksandrovich Bonch-Osmolovsky] at [[Chessgames.com]]</ref> (3.Nf3 Ne7) aims to defend the f4-pawn with ...Ng6, a relatively safe square for the knight compared to the Schallopp Defense. It was played by [[Mark Bluvshtein]] to defeat former world title finalist [[Nigel Short]] at [[Montreal]] 2007,<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1468060 |title=Short vs. Bluvshtein, Montreal 2007 |website=[[Chessgames.com]] }}</ref> even though it has never been highly regarded by theory.

==== Cunningham Defense: 3...Be7 <span id="Cunningham Defense"></span> ====
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|Sample position in the Cunningham Defense
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The [[Alexander Cunningham (jurist)|Cunningham]] Defense (3.Nf3 Be7) threatens a check on h4 that can permanently prevent White from castling; furthermore, if White does not immediately develop the king's bishop, Ke2 would be forced, which hems the bishop in. A sample line is 4.Nc3 Bh4+ 5.Ke2 d5 6.Nxd5 Nf6 7.Nxf6+ Qxf6 8.d4 Bg4 9.Qd2 ({{em|diagram}}). White has strong central control with pawns on d4 and e4, while Black is relying on the white king's discomfort to compensate.

To avoid having to play Ke2, 4.Bc4 is White's most popular response.<ref>{{cite web |url=http://www.chessgames.com/perl/explorer?node=2624107&move=4&moves=e4.e5.f4.exf4.Nf3.Be7&nodes=21720.21721.101115.1367170.1367171.2624107 |title=Chess Opening Explorer |website=[[Chessgames.com]] |access-date=7 June 2016 }}</ref> Black can play 4...Bh4+ anyway, forcing 5.Kf1 (or else the wild [[Joseph Bertin|Bertin]] Gambit or Three Pawns' Gambit, 5.g3 fxg3 6.0-0 gxh2+ 7.Kh1, played in the nineteenth century). In modern practice, it is more common for Black to simply develop instead with 4...Nf6 5.e5 Ng4, known as the Modern Cunningham. An under-explored but seemingly playable line here is 5...Ne4!?, the [[Max Euwe|Euwe]] Variation, which has a number of trappy ideas.

==== Schallopp Defense: 3...Nf6 <span id="Schallopp Defense"></span> ====
The [[Emil Schallopp|Schallopp]] Defense (3.Nf3 Nf6) is usually played with the intention of holding on to the pawn after 4.e5 Nh5. While it is not Black's most popular option, it attracted some attention in 2020 when [[Ding Liren]] used it to beat Magnus Carlsen in the online [[Magnus Carlsen Invitational]] tournament. The undefended knight on h5 means Black must be careful: for example 4.e5 Nh5 5.d4 d6 6.Qe2 Be7? (correct is 6...d5!=) 7.exd6 Qxd6 8.Qb5+ wins the h5-knight.<ref>Shaw, p. 406</ref>

==== Modern Defense: 3...d5 <span id="Modern Defense"></span> ====
The Modern Defense, or [[Opatija|Abbazia]] Defense,<ref>The name comes from a [http://www.chess.com/chessopedia/view/abbazia-defense tournament] {{Webarchive|url=https://web.archive.org/web/20141018151356/http://www.chess.com/chessopedia/view/abbazia-defense |date=2014-10-18 }}, played in Abbazia in 1912, in which all the games had to be a King's Gambit Accepted. The town, at the time in the [[Austria-Hungary]] empire, is now in modern [[Croatia]]</ref> (3.Nf3 d5) has much the same idea as the Falkbeer Countergambit, and can in fact be reached via transposition, i.e. 2...d5 3.exd5 exf4 4.Nf3. Black concentrates on gaining piece play and fighting for the [[initiative (chess)|initiative]] rather than keeping the extra pawn. It has been recommended by several publications as an easy way to equalize, although White's extra central pawn and piece activity gives a slight advantage. If White captures (4.exd5) then Black may play 4...Nf6 or recapture with 4...Qxd5, at which point it becomes the [[Scandinavia]]n Variation of {{chessgloss|KGA}}. This variation was considered most critical in the past, but recent trends seem to indicate a slight advantage for White.

==== Fischer Defense: 3...d6 <span id="Fischer Defense"></span> ====
{{Main|King's Gambit, Fischer Defense}}
"The refutation of any gambit begins with accepting it. In my opinion the King's Gambit is busted. It loses by force." —&thinsp;R. Fischer, "A Bust to the King's Gambit"

The Fischer Defense (3.Nf3 d6), although previously known, was advocated by [[Bobby Fischer]] after he was defeated by [[Boris Spassky]] in a Kieseritzky Gambit at the 1960 [[Mar del Plata chess tournament|Mar del Plata tournament]]. Fischer then decided to refute the King's Gambit, and the next year the ''[[American Chess Quarterly]]'' published his analysis of 3...d6, which he called "a high-class waiting move".<ref name="FischerBusttext"/><ref name="FischerBustPDF"/>

{{Chess diagram small
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| Fischer Defense after 6.Ng1
}}
The point is that after 4.d4 g5 5.h4 g4 White cannot continue with 6.Ne5 as in the Kieseritzky Gambit, 6.Ng5 is unsound because of 6...f6{{chesspunc|!}} trapping the knight, and 6.Nfd2 blocks the bishop on c1. This leaves the move 6.Ng1 as the only option, when after six moves neither side has developed a piece. The resulting slightly odd position ({{em|diagram}}) offers White good attacking chances. A typical continuation is 6.Ng1 Bh6 7.Ne2 Qf6 8.Nbc3 c6 9.g3 f3 10.Nf4 Qe7 with an unclear position (Korchnoi/Zak).

The main alternative to 4.d4 is 4.Bc4. Play usually continues 4...h6 5.d4 g5 6.0-0 Bg7, transposing into the Hanstein Gambit, which can also be reached via 3...g5 or 3...h6.

==== MacLeod Defense: 3...Nc6 <span id="MacLeod Defense"></span> ====
The MacLeod Defense, 3...Nc6, is named after [[Nicholas MacLeod]]. [[Joseph Gallagher|Joe Gallagher]] writes that 3.Nf3 Nc6 "has never really caught on, probably because it does nothing to address Black's immediate problems." Like Fischer's Defense, it is a {{chessgloss|waiting move}}.<ref>[[Joseph Gallagher|Joe Gallagher]], ''Winning with the King's Gambit'', Henry Holt, 1993, p. 105. {{ISBN|0-8050-2631-2}}.</ref> An obvious drawback is that the knight on c6 may prove a target for the d-pawn later in the opening.

==== Wagenbach Defense: 3...h5 <span id="Wagenbach Defense"></span> ====
An invention of the Hungarian/English player, János Wagenbach. [[John K. Shaw|John Shaw]] writes: "If given the time, Black intends to seal up the kingside with ...h4 followed by ...g5, securing the extra pawn on f4 without allowing an undermining h2–h4. The drawback is of course the amount of time required".<ref>[[John K. Shaw|John Shaw]], ''The King's Gambit'', Quality Chess, 2013, p. 431. {{ISBN|978-1-906552-71-8}}.</ref>

=== Bishop's Gambit: 3.Bc4 <span id="Bishop's Gambit"></span> ===
{{main|Bishop's Gambit}}
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|Bishop's Gambit: 3.Bc4
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Of the alternatives to 3.Nf3, the most important is the Bishop's Gambit, 3.Bc4. White allows 3...Qh4+ 4.Kf1, losing the right to castle, but this loses time for Black after the inevitable Nf3 and White will develop rapidly. White also has the option of delaying Nf3, however, and can instead play g3{{chesspunc|!?}}, after which the game becomes quite sharp, with White having the option of Qf3 with an attack on f7, or Kg2 threatening hxg3. This idea is advocated, among others, by GM [[Simon Williams (chess player)|Simon Williams]].<ref>{{Citation |last=ChessBaseProducts |title=Simon Williams – King's Gambit Vol.1 |date=2014-05-27 |url=https://www.youtube.com/watch?v=okkZH4y3j40|access-date=2019-02-24 }}</ref>

Korchnoi and Zak recommend as best for Black 3...Nf6 4.Nc3 c6, or the alternative move order 3...c6 4.Nc3 Nf6. After 5.Bb3 d5 6.exd5 cxd5 7.d4 Bd6 8.Nge2 0-0 9.0-0 g5 10.Nxd5 Nc6, Black was somewhat better in Spielmann–Bogoljubow, Märisch Ostrau 1923.<ref>{{cite web |url=http://www.chessgames.com/perl/chessgame?gid=1030741 |title=Spielmann vs. Bogoljubow, Märisch Ostrau 1923 |website=[[Chessgames.com]] }}</ref>

Black's other main option is 3...d5, returning the pawn immediately. Play might continue 3...d5 4.Bxd5 Nf6 5.Nc3 Bb4 6.Nf3 Bxc3 7.dxc3 c6 8.Bc4 Qxd1+ 9.Kxd1 0-0 10.Bxf4 Nxe4 with an equal position (Bilguer Handbuch, Korchnoi/Zak).

3...Nc6!?, Maurian Defense, is relatively untested, but if White plays 4.Nf3 Black can transpose into the Hanstein Gambit after 4...g5 5.d4 Bg7 6.c3 d6 7.0-0 h6 (Neil McDonald, 1998). John Shaw wrote that 3...Nc6 is a "refutation" of the Bishop's Gambit, as he says that Black is better in all variations.

Steinitz's 3...Ne7 and the {{chessgloss|countergambit}} 3...f5 (best met by 4.Qe2!) are generally considered inferior.

=== Other 3rd moves for White ===
Other 3rd moves for White are rarely played. Some of these are:
* 3.Nc3 ([[James Mason (chess player)|Mason]] Gambit or [[Paul Keres|Keres]] Gambit)
* 3.d4 (Villemson Gambit<ref>Named after Martin Villemson (1897–1933) of [[Pärnu]], [[Estonia]], editor of the chess magazine ''Eesti Maleilm''. See ''Oxford Companion to Chess'', Oxford University Press, Oxford, UK, 1984</ref> or [[Wilhelm Steinitz|Steinitz]] Gambit)
* 3.Be2 (Lesser Bishop's Gambit or [[Savielly Tartakower|Tartakower]] Gambit)
* 3.Qf3 ([[Gyula Breyer|Breyer]] Gambit or Hungarian Gambit)
* 3.Qe2 (Basman Gambit)
* 3.g3 (Gama Gambit)<ref>[https://paperspast.natlib.govt.nz/newspapers/ESD19141017.2.25?items_per_page=100&query=%22Gama+Gambit%22&snippet=true Game No. 981], ''[[Evening Star (Dunedin)|Evening Star]]'', [[Dunedin]], New Zealand, 17 October 1914</ref>
* 3.h4 ([[Philip Stamma|Stamma]] Gambit)
* 3.Nh3 ([[Louis Eisenberg|Eisenberg]] Gambit)
* 3.Kf2?! (The Tumbleweed)<ref>{{cite book |last=Soltis |first=Andy |author-link=Andrew Soltis |title=Chess to Enjoy |publisher=[[Stein and Day]] |year=1978 |pages=[https://archive.org/details/chesstoenjoy00solt/page/171 171–72] |isbn=0-8128-2331-1 |url-access=registration |url=https://archive.org/details/chesstoenjoy00solt/page/171 }}</ref>