Exchange Variation, Chameleon Variation

The Chameleon Variation keeps White's usual Exchange setup of Bd3, Qc2 and Nge2. After 8...Re8 9. Nge2 Nf8, however, White plays 10. O-O-O instead of castling short and preparing f3 and e4. With the kings on opposite wings, the Carlsbad structure takes on a sharper character. White's kingside pawns become attacking units against the black king. Black looks for counterplay on the queenside, where White's king now stands, and through the e4 square and the half-open e-file.