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 16th century by Giulio Cesare Polerio and then the 17th century by Gioachino Greco, after whom it is sometimes named.

It is an aggressive but objectively dubious opening for Black which often leads to wild and tricky positions.

[1][2] FIDE Master Dennis Monokroussos even goes so far as to describe it as "possibly the worst opening in chess".

[3] While Paul van der Sterren observes: What is required to play the Latvian Gambit with any degree of success is a sharp eye for tactics and a mental attitude of total contempt for whatever theory has to say about it.The Latvian is, and has always been, uncommon in top-level over-the-board play, but some correspondence players are devotees.

[2][4] The ECO code for the Latvian Gambit is C40 (King's Knight Opening).

The opening was originally known as the Greco Countergambit, and some modern writers still refer to it as such.

[5] That name recognised the Italian player Gioachino Greco (1600–1634), who contributed to the early theory of the opening.

(The terms "Vorhand" and "Rückhand" were used before the standard that White moves first was adopted in the mid-19th century).

The Austrian master Albert Becker once published an article that Bētiņš judged to be dismissive about the Latvian Gambit.

[citation needed] According to most, the opening's only advantage is its ostensible novelty value, since, irrespective of what level you play at, the chances of your opponent even knowing this opening, let alone knowing the best lines for White, are low.

However, it has been used by Boris Spassky[6] and Mikhail Chigorin,[7] amongst many others; albeit, usually in casual play.

After the usual 3...Qf6, the traditional main line has been 4.d4 d6 5.Nc4 fxe4, however recently the immediate 4.Nc4 (the Leonhardt Variation) has become popular.

!, against which John Nunn recommends 4.d4, preferring principled opening play to the unclear tactics resulting from 4.Qh5+.

[18] 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!

According to Latvian Gambit experts Kon Grivainis and John Elburg, Black wins more often than White in this line.

[23] Sharper is 6...hxg6, when 7.Qxh8 Kf7 9.Qd4 Be6 gives White a large material advantage, but his "position is constantly on the edge of a precipice", and the line has accordingly fallen out of favour.

Some sample continuations are Assessment: Black is usually down material, but has excellent compensation.

[27] White's 3.Nc3 was originally analysed by the American master Stasch Mlotkowski (1881–1943) in the 1916 British Chess Magazine.

7.Nf7 Qe8 8.Nxh8 Nxh5 9.Nc3 Kg8 Black lost castle and exchanged its Rook with White Knight and Bishop, but kingside is solid, ready to expand queenside, which is considered to be equal.

Sample Continuation #2 4.Nxe5 Nf6 5.Be2 d6 6.Ng4 Be7 7.Nc3 d5 8.Ne5 O-O 9.Bg5 c6 10.O-O Bf5 Assessment: Black has a better pawn structure, and better bishops.