Editing King's Gambit (section)

==== 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>