Chess Opening Theory/1. d4/1...d5/2. c4/2...c6/3. Nf3/3...Nf6/4. Nc3/4...dxc4/5. a4/5...Na6

Black develops the knight to a6 in order to later transfer it to b4, which was weakened by White's move 5. a4. This does however give White time to occupy the center with 6. e4, or to support the d-pawn with 6. e3.

Regardless of whether White pushes the e-pawn one or two squares, Black's response is going to be 6...Bg4, pinning the knight on f3 to the white queen. This is different from the Steiner variation, where the knight isn't actually pinned and can move to e5, gaining a tempo on the bishop.

After 6. e4 Bg4 7. Bxc4 it is possible for Black to play 7...Bxf3, doubling White's pawns since 8. Qxf3 would lose the d4 pawn. Despite being a pawn down, this position is still fine for White who can choose to create doubled pawns on Black's a-file with 9. Bxa6. A more modest approach is 7...e6, blunting White's light-squared bishop.

This opening is named after the Russian GM Vasily Smyslov. While not the first person to play this variation (the position was reached before in 1926^[1]), he popularized it in 1959.^[2] The move has lost its popularity over time, being mostly used as a surprise weapon.

1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Na6

• Gligoric vs Smyslov, 1959 https://www.chessgames.com/perl/chessgame?gid=1125878