Taimanov Variation, Szén Variation

With 5. Nb5 White goes straight for the weakness on d6 created by 2...e6. The knight and the queen both bear on that square, while only the dark-squared bishop guards it, so the reflexive 5...a6? runs into 6. Nd6+ Bxd6 7. Qxd6, conceding the bishop pair and leaving the white queen deep in Black's camp. The most frequent reply is 5...d6, which opens the queen's line to d6. White usually continues 6. c4 or 6. Bf4, but the b5-knight must eventually retreat, ending up with knights on a3 and c3 or on c3 and d2.

The central counter 5...d5 also covers d6 on paper, but after 6. exd5 exd5 7. Bf4 White regains control of the square, and White scores heavily in practice. A more flexible choice is 5...Nf6, which hits e4 and delays Nd6. After 6. N1c3 Black can return to ...d6 or play 6...Bb4, when 7. a3 Bxc3+ 8. Nxc3 d5 frees the position. The engine regards the starting position as roughly balanced.