French Defence

By advancing the d pawn two squares black poses an immediate challenge to the powerful white center. The white player must now react by either advancing the pawn which will lead to the advance variation where he/she will get to put immediate pressure on the black king side, but black will have more than enough to put the pawn wedge under serious attack with moves like c5, Nc6, Qb6 and Nh6 (followed obviously by Nf5).

Another choice for white is to defend the pawn with either Nc3 or Nd2. Out of these two possible defenses, the first is the most common as it does not block the bishop on c1 and puts some mild pressure on d5. Black has many possible answers, however, including the Winawer variation (3...Bb4), which leads to extremely complex positions (which are usually closed). Therefore the amount of theory behind Nc3 is too big and too complex for the move to be played lightly.

Nd2, on the other hand, is much safer but also less ambitious and harder to get an advantage with. Black will have the choice of either forcing e5 (with 3...Nf6) and attacking the pawn wedge at both base and head with the breaks c5 and f6, or exchanging an isolated d pawn for active pieces with 3...c5.

Finally, white may try the exchange variation 3 exd5, which is unambitious and gives black equal chances, but avoids the complications of the other variations.