Mexican Defense

The Mexican Defense arises after 1. d4 Nf6 2. c4 Nc6, when Black brings out the queen's knight before committing any central pawn. It is also known as the Black Knights' Tango and the Kevitz-Trajkovich Defense, and is classified under ECO code A50. The knight on c6 departs from the usual Indian development. Instead of choosing between ...e6, ...g6 or ...d5, Black keeps the pawn structure open to several setups and prepares the ...e5 break, which would challenge d4 directly.

Long regarded as obscure, the line was revived by Georgi Orlov, whose books on the Black Knights' Tango gave it a body of theory. It remains a sideline. Engines give White a slight edge, but Black's practical results in online play are respectable, and decisive games are much more common than draws.

White's three main replies handle the knight in different ways. 3. Nc3, the most frequent choice, develops normally and lets Black strike with ...e5. 3. Nf3 controls e5 and so discourages that break; among the main options it gives White the best results. 3. d5 gains space and drives the knight away at once. The knight can retreat or go to e5, from where it eyes the c4-pawn.

After 3. d5 Ne5, the Horsefly Gambit 4. f4 ignores the attack on c4 and chases the knight again. Because the bishop on f1 cannot defend c4 while the e-pawn is still on e2, Black can take the pawn with 4...Nxc4. White's compensation is a broad pawn center and gains of time against the black knight. This makes the line much sharper than the positional play that usually follows 3. Nc3 or 3. Nf3.

In all these lines the play depends on whether Black achieves ...e5 under good circumstances or White restrains it and uses the extra central space. The early knight move gives Black a less familiar game than the main Indian systems.