Rubinstein System, Rubinstein Variation, Main Line

With 7. a3 White puts the question to the bishop on b4 at once, aiming to secure the bishop pair or gain time. The retreat 7...Be7 is by far the most frequent answer, while 7...Bxc3+ and 7...Ba5 are rarer. After 7...Be7, Kasparov experimented in his youth with 8. d5 exd5 9. cxd5, grabbing more space at the cost of development; 8. Nf4 is the more cautious alternative. The engine gives White a slight edge.