Mark's Opening

Mark's Opening is a chess opening characterized by the moves:

1 d4 Nf6
2 Nc3 d5
3 Bf4

The position after white's 3rd move can be reached with different move orders, ie white can play Bf4 and then Nc3; and black can play d5 before Nf6.
Mark's Opening is a recent invention, which aims to control the centre and develop white's pieces quickly.
The main line continues:

3 ... Bf5
4 Nf3 e6
5 e3 Bd6
6 Bd3 Bxf4
7 exf4 Bg4
8 h3 Bxf3
9 Qxf3 0-0
10 0-0 Qd6
11 Ne2 c5
12 c3 Nbd7
13 Rfe1

6 Ne5 is also good for white (instead of Bd3).
In most variations of Mark's Opening, white plays 4 Nf3, 5 e3, and then 6 Bd3.

Black defences other than 3 ... Bf5

3 ... Bg4
4 Nf3 Nc6
5 e3 e6
6 Be2 Bd6
7 Ne5 Bxe2
8 Qxe2 Bxe5
9 Bxe5 Nxe5
10 dxe5 Nd7

White can then play f4, and castle soon afterwards.

3 ... Nc6

Possibly the strongest variation for white here is 4 Nf3 Bg4 and then exactly as above (ie it's simply a case of black's 3rd and 4th moves being played the other way round). An alternative is to play e3 first, and then Nf3:
4 e3 Bf5
5 Nf3 e6
6 Bd3

3 ... g6
4 Nf3 Bg7

and this variation transposes into the Grunfeld reversed/symmetrical variation.

3 ... c5
4 e3 e6
5 Nf3 Be7
and then white has 2 good alternatives here. He can play Bd3 or Bb5.

Alternative 4th moves for black

After 1 d4 Nf6, 2 Nc3 d5, 3 Bf4 Bf5, 4 Nf3 black can also play

4 ... c5
5 e3

and then black has 2 alternatives. He can either play 5 ... Nc6, in which case white plays either Bb5 or Bd3; or black can try to break in the centre with 5 ... cxd4; in which case white plays Nb5, threatening to fork the king and rook with Nc7.
This variation does demonstrate the main weakness of Mark's Opening. The early Nc3 blocks the c pawn in. However, it's likely that white will be able to play e4 to break in the centre himself. In some positions, it can be useful to back this up with the move f3, after having castled queenside, as in the Veresov Attack.

Alternative 5th moves for black

After 1 d4 Nf6, 2 Nc3 d5, 3 Bf4 Bf5, 4 Nf3 e6, 5 e3, black has 2 alternatives:

5 ... Bb4 pinning the knight. After 6 Bd3, black can then double white's pawns with 6 ... Bxc3, 7 bxc3. White should be able to play c4 later and exchange pawns to relieve himself of that positional weakness.

5 ... c5
6 Bd3

and here black has 2 alternatives: 6 ... cxd4, in which case white plays 7 Nb5; or black can simply exchange bishops with 6 ... Bxd3 7 Qxd3.

A different idea for black

Another idea seen in games for black is to play an early c6, then pin the knight on c3 with Bb4, backed up by Qa5. A timely a3 by white should prevent any real problems here.

Very brief comparison with the Veresov Attack

The Veresov Attack has been played by, among others, Boris Spassky, Mikhail Tal, and Vassily Smyslov, and is identical to Mark's Opening except for the 3rd move, the Veresov Attack goes Bg5 instead of Bf4. Bf4 gives white more control of the centre. As mentioned earlier, Mark's Opening can be played in a similar way to the Veresov Attack, with queenside castling, and then the move f3 to support a break in the centre with e4.

For more information

www.Marksopening.blogspot.com