Fianchetto Variation, Panno Variation

The Panno Variation (ECO E63) meets the Fianchetto Variation with 6...Nc6 and 7...a6. The knight presses on d4 and keeps ...e5 available, while ...a6 prepares ...Rb8 and ...b5, opening the queenside against the c4-pawn. White's three main replies are about equally popular at the top. 8. e4 builds a broad center. 8. d5 gains space and drives the knight away. 8. b3 is a quieter choice that shores up c4. Engines give White a slight edge. Online results are close to level, and Black does well against 8. e4.

After 8. d5 Na5 9. Nd2 c5 10. Qc2, the knight on the rim and the ...b5 break both aim at c4. The Blockade Line, 10...e5, fixes the center. The Donner Line instead plays 10...Rb8 11. b3 b5 12. Bb2 bxc4 13. bxc4 Bh6. Black opens the b-file and reroutes the bishop to h6, where it eyes d2. The Korchnoi Line, 8. h3 Rb8 9. Be3 b5 10. Nd2, keeps the pawn on d4. White's h3 rules out ...Ng4, and the knight goes to d2 to meet the queenside advance.