Central Variation, Greco Variation

In the Greco Variation, Black meets the Central Variation, 3. e4, by defending c4 with 3...b5 rather than returning the pawn for development. The e4-pawn blunts the long diagonal for now, but the pawn costs Black time and leaves the queenside chain loose. By far the most common reply is 4. a4, which strikes at the base of the chain, with 4. Nc3 the second choice. The standard sequence is 4. a4 c6 5. axb5 cxb5 6. Nc3. 5. Nc3 and Greco's own 6. b3 are the alternatives. Once the a8-h1 diagonal opens, Black must reckon with discovered attacks and queen-and-bishop batteries, and b5 remains a target.

After 6. Nc3 Black chooses between the traditional 6...Bd7 and the modern 6...a6 and 6...Qb6. The last of these revived the line in the 2020s. Both modern moves tend to involve giving up the exchange. One example is 6...a6 7. Nxb5 axb5 8. Rxa8 Bb7. Another is 6...Qb6 7. Nd5 Qb7 8. Bf4 e5 9. Bxe5 Nd7 10. Bf4 Ngf6 11. Nc7+ Kd8 12. Nxa8 Qxe4+ 13. Ne2 Qxa8. Against 6...Qb6 White also tries 7. b3 and 7. Be3. The variation stays uncommon at a serious level, and the engine gives White a slight edge.