Latvian Gambit

The Latvian Gambit (or Greco Countergambit) is a chess opening characterised by the moves:
It is one of the oldest chess openings, having been analysed in the 17th century by Gioachino Greco, after whom it is sometimes named. The opening has the appearance of a King's Gambit with colours reversed. It is an aggressive but rather dubious choice for Black which often leads to wild and tricky positions. FIDE Master Dennis Monokroussos even goes so far as to describe it as "possibly the worst opening in chess". As assessed by Paul van der Sterren:
The Latvian is uncommon at the top level of play, but some correspondence players are devoted to it.
The "ECO" code for the Latvian Gambit is C40 (King's Knight Opening).
History.
The opening was originally known as the Greco Countergambit, and some modern writers still refer to it as such. That name recognised the Italian player Gioachino Greco (1600–1634), who contributed to the early theory of the opening. The name "Latvian Gambit" is a tribute to the Latvian players, notably Kārlis Bētiņš, who analysed it in the early part of the 20th century.
White's third move.
Many responses for White have been analysed. The most important of these are:
3.Nxe5.
White's 3.Nxe5 is the main line. After the usual 3...Qf6, White chooses between 4.d4 d6 5.Nc4 fxe4 and the immediate 4.Nc4, which has the advantage of allowing White to open the center with d3, for example 4...fxe4 5.Nc3 Qg6?! 6.d3 exd3? 7.Bxd3 Qxg2? and now White is winning after 8.Qh5+ Kd8 (or 8...g6 9.Qe5+ and 10.Be4) 9.Be4. However, if 6... Bb4, white must be careful following the same line, e.g. 7. Bd2 exd3 8. Bxd3 Qxg2 9. Qh5+ Kd8 10. Be4 Nf6! because now if white plays Bg5, which would be necessary to win the queen in the earlier line, then Bxc3+ wins for black. The main line continues 5...Qf7 6.Ne3! Black usually responds with 6...c6!?, when White can either accept the pawn sacrifice with 7.Nxe4 d5 8.Ng5 Qf6 9.Nf3, or decline it with the more popular 7.d3 exd3 8.Bxd3 d5 9.0-0. The latter variation has been deeply analysed; the British grandmaster Anthony Kosten analyses one line to move 32. One line discussed by International Master Jeremy Silman is 9...Bc5 10.Na4 Bd6 11.c4 d4 12.Nc2 c5 13.b4 Ne7 14.Nxc5 Bxc5 15.bxc5 Nbc6 16.Bb2 0–0 17.Nxd4 Nxd4 18.Bxd4 Bf5 19.Bxf5 Nxf5 20.Be3 Qxc4 21.Qb3 Nxe3!? 22.fxe3 Rxf1+ 23.Rxf1 Qxb3 24.axb3 Rc8 25.Rf5 and now 25...Rd8 or 25...Rc6 gives Black an excellent chances to draw the pawn-down endgame. Silman later argued that 10.b4!! and now 10...Bxb4 11.Ncxd5 cxd5 12.Nxd5 or 10...Bd6 11.Re1! Ne7 12.Nexd5 cxd5 13.Nb5 is close to winning for White, and that the "old, discredited" 9...Bd6 (rather than 9...Bc5) might be Black's best try, though still insufficient for .
Also possible is the eccentric 3...Nc6?!, against which John Nunn recommends 4.d4. After 4.d4, Kosten analyses 4...Qf6!? 5.Nc3 Bb4 6.exf5! Nxe5 7.Qe2. Instead of 4.d4, Kosten says that White can accept the proffered rook with 4.Qh5+ g6 5.Nxg6 Nf6 6.Qh3 hxg6 7.Qxh8 Qe7 (7...fxe4? 8.d4! is strong) 8.d3! (Stefan Bücker gives an alternative 8.Nc3! Nb4 9.d3 as also winning for White) 8...fxe4 9.Be3 d5 10.Bc5! Qxc5 11.Qxf6 Bf5 12.dxe4 Nd4 13.exf5! Nxc2+ 14.Kd1 Nxa1 15.Bd3 Qd6 16.Re1+ Kd7 17.Qf7+ Be7 18.Re6 winning.
3.Bc4.
White's 3.Bc4 may lead to perhaps the most notorious and heavily analysed line of the Latvian, which begins 3...fxe4 4.Nxe5 Qg5 5.d4 Qxg2 6.Qh5+ g6 7.Bf7+ Kd8 8.Bxg6! Qxh1+ 9.Ke2 Qxc1 (9...c6 is a major alternative) 10.Nf7+ Ke8 11.Nxh8+ hxg6 12.Qxg6+ Kd8 13.Nf7+ Ke7 14.Nc3! ("diagram").
Instead of 4...Qg5, however, "nowadays players often give preference to 4...d5", the Svedenborg or Polerio Variation. According to Latvian Gambit experts Kon Grivainis and John Elburg, Black wins more often than White in this line. After 4...d5 5.Qh5+ g6 6.Nxg6, Black chooses between 6...Nf6 and 6...hxg6. 6...Nf6 usually leads, after 7.Qe5+ Be7 8.Bb5+! c6 9.Nxe7 Qxe7 10.Qxe7+ Kxe7 11.Be2 (11.Bf1!?), to an endgame where Black is a pawn down but has considerable positional compensation. Sharper is 6...hxg6, when 7.Qxh8 Kf7 9.Qd4 Be6 gives White a large advantage, but his "position is constantly on the edge of a precipice", and the line has accordingly fallen out of favour. More often, White plays 7.Qxg6+ Kd7 8.Bxd5 Nf6, leading to sharp and unclear play.
3.Nc3.
White's 3.Nc3 was originally analysed by the American master Stasch Mlotkowski (1881–1943) in the 1916 "British Chess Magazine". Kosten gives as Black's two main responses 3...Nf6 4.Bc4 (4.exf5 is also possible) fxe4 5.Nxe5 d5 6.Nxd5! Nxd5 7.Qh5+ g6 8.Nxg6! hxg6! 9.Qxg6+ Kd7 10.Bxd5 Qe7 11.Qxe4 Rh4 12.Qxe7+ Bxe7, reaching an endgame where White has four pawns for a , and 4...fxe4 5.Nxe5 Qf6, when White can choose from 6.Nc4! (transposing to the main line 3.Nxe5 Qf6 4.Nc4 fxe4 6.Nc3), 6.d4, and 6.f4!? Black can also play 3...d6, when 4.d4 to the Philidor Countergambit (1.e4 e5 2.Nf3 d6 3.d4 f5!?), which was favoured by Paul Morphy in the mid-19th century and is still seen occasionally today.
3.exf5.
White's 3.exf5 followed by e4 4.Ne5 Nf6 5.Be2 is recommended by John L. Watson and Eric Schiller. 4.Qe2, 4.Nd4, and even 4.Ng1!? (leading to a sort of King's Gambit with colours reversed) are also possible.
3.d4.
White's 3.d4 followed by fxe4 4.Nxe5 Nf6 5.Bg5 d6 leads, as usual, to sharp play. White often offers a piece with either 6.Nc3!? or 6.Nd2!?, but Black seems to have adequate resources against both.