Four Knights Variation, Exchange Variation

By exchanging on c6 at once, White steers away from the Sveshnikov transfer that 6. Ndb5 allows and removes the knight before Black can reorganize. The point is the follow-up 7. e5, which drives the f6-knight from its post. Black nearly always recaptures 6...bxc6, taking back toward the center so that the c- and d-pawns can support ...d5. The main line runs 6...bxc6 7. e5 Nd5 8. Ne4, with the white knight centralized in front of the e5-pawn, which gives White space on the kingside and fixes Black's structure. Black in turn gets the half-open b-file and the chance to undermine e5. The recapture 6...dxc6 is a rare alternative that opens the d-file toward the queens and gives up central control, and Black scores noticeably worse after it. The zwischenzug 6...Bb4 is seldom played, and White's results against it are overwhelming.

This is the most common answer to the Four Knights move order. The engine assesses the position as a slight edge for White, but practical results are close to even, with Black scoring marginally better.