Chess Opening Theory/1. d4/1...Nf6/2. c4/2...e6/3. Nf3

Indian Defence with e6, Nf3
3. Nf3 develops a piece and contributes to White's fight for the center of the board. This move strengthens the d4 and e5 squares and brings White a move closer to castling kingside. Nf3 blocks the f-pawn, which can be a powerful lever for White in some lines, but White has many other options as well. This continuation is often chosen by White players who are trying to avoid the Nimzo-Indian Defence, 3. Nc3 Bb4. 3...Bb4+ is still possible after 3. Nf3, but this usually leads to the Bogo-Indian Defence, which has a much poorer theoretical reputation for Black than the Nimzo-Indian.

Because it blocks the f-pawn, does not support the e4 pawn break, and does not fight for the d5 square, 3. Nf3 is a little more passive on White's part than 3. Nc3. Nevertheless, it is solid, and there are many ways for White to get a quiet, positional advantage. Apart from the Bogo-Indian, Black can aim for the Queen's Indian or Benoni as well as the usual transpositions:
 * 3...b6 - The Queen's Indian (QID). This move is quiet and aims at equality via active piece play, trades in the center, and freeing pawn breaks such as ...c5, ...d5 or even ...e5 (usually utilizing ...d6 as preparation for this)
 * 3...d5 - as always, the Queen's Gambit Declined (QGD) transposition is in the air.
 * 3...c5 - is the Benoni... This is one of the more appealing paths to the Benoni as it avoids the dangerous f2-f4 lines.

Theory table
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'''1. d4 Nf6 2. c4 e6 3. Nf3'''