Spanish Variation, Rubinstein Variation Accepted

With 5. Nxd4, also called the Exchange Variation, White removes the knight that challenged the bishop and f3, declining both the complications of 5. Nxe5 and the theory of 5. Ba4. Black recaptures 5...exd4 in nearly every game. The pawn on d4 hits the c3 knight, and White usually answers with the forcing 6. e5 dxc3 7. exf6 Qxf6 8. dxc3, a series of exchanges that empties the center and leaves a symmetrical, simplified structure. The intermediate 7...cxd2+ is risky, since 8. Bxd2 Qxf6 9. O-O gives White a dangerous lead in development. After 8. dxc3, Black can offer the queen trade with 8...Qe5 9. Qe2 Qxe2+ 10. Bxe2, while 8...Bc5 and 8...c6 keep queens on.

The line has a reputation for producing dry, equal positions, and that drawish quality deters many players who adopt 4...Nd4 hoping for an unbalanced fight. Engines rate the position as level. In online games Black nonetheless scores a little better than White. The rare alternatives 5...c6 and 5...Nxe4 are seldom seen.