Williams Variation

The Williams Variation is Black's way of keeping the Nimzowitsch Defense independent after 2. Nf3. Instead of 2...e5, which would allow a transposition to the double king-pawn openings, Black supports a later ...e5 with the d-pawn and keeps the knight on c6. The move is solid but less dynamic than other second moves, and if Black handles it passively the game can become a worse version of the Pirc Defense. The engine gives White a slight edge, and results are close to even with a modest plus for White.

The most common reply by far is 3. d4, taking the broad center, while 3. Bc4 and 3. Nc3 are the main developing alternatives. After 3. d4 Black fights for the center with pieces, either through 3...Nf6 or the main line 3...Bg4, pinning the knight that defends d4. Then 4. Bb5 a6 5. Bxc6+ leads to a roughly level game, whereas 4. d5 Ne5 5. Nxe5, the Keene Attack named after Raymond Keene, gives up the queen after 5...Bxd1 and wins it back with 6. Bb5+ c6 7. dxc6.