Fianchetto Variation, Debrecen Defense

The Debrecen Defense is reached when White develops with g3, Bg2, Nc3 and Nf3 before castling, and Black answers with 6...Nbd7. The knight supports the ...e5 advance and keeps the c-pawn free, so Black adopts the Classical approach to the Fianchetto Variation before White has committed the king. Black's plan is to challenge d4 with ...e5, then either hold the tension with ...c6 or exchange on d4 and play against White's center with the rooks and queenside pawns.

White's usual reply by a wide margin is 7. O-O, which transposes to the Classical line normally reached through 6. O-O Nbd7 7. Nc3. The main alternative is 7. e4, which occupies the center at once and leaves castling for later. 7. Bg5 is rarely played. The line sees moderate use, ranking well inside the most common third of named openings. Engines give White a slight edge, while online results are fairly close, with White scoring a little better.