The Mar del Plata Attack: The Neo-Classical Line, 13. a4
Photographer: Fermin Rodriguez Penelas,

The Mar del Plata Attack: The Neo-Classical Line, 13. a4

We're going to continue looking at the Neo-Classical line of the KID, starting on the 13th move. Last time I gave the four 13th moves that we are going to look at, and we will start with the most common and main line:
13. a4
This is the most commonly played move at the higher level, however at my level I do not see this move much, either meaning that my opponents do not know much theory, do not understand the move, or prefer another move.
13. a4 doesn't seem to be doing much, but in many cases the a7 pawn will be targeted by the bishop on f2 and the c3 knight jumping to b5. The a-pawn will advance further if black allows, take space, and extend the a-file for the queenside rook, which can go to the c-file or lift if it wants. In many lines black will give up the a-pawn for an attack on the kingside, but it does not usually work out well for black, so here I would suggest the move 13...a5. The most commonly played, by a very small margin, is 13...Ng6, but 13...a5 appeals more to me, seems to make more sense and be better.

This gets the pawn off the vulnerable a7 square, and delays white's play with b2-b4 for a tiny little bit of time. The drawback is that it takes some time away from black's kingside attack. One main idea in this line is to play ...b6, which attempts to secure control over the very important c5 square. It does weaken c6, however. Here are the next few moves, which are almost always played and most obvious.

This is where I will have to leave off with the specific moves. After this anything can happen, and you will have to use your knowledge of the position to outplay your opponent, so you have to be well equipped with ideas and plans of the position rather than just moves here.
But before that, there's a trap you need to know in this position.
Now let's get see what we should do.
Take a look at the position again.
Black, as usual, wants to attack on the kingside. He will play for h7-h5 and g5-g4, although in some cases g5-g4 does not need to be prepared with h7-h5. The pawns will roll down the board and break open the white king's cover so the pieces can flow in and finish it.
White will play a4-a5 to break open the queenside for an attack. It can come very fast, so black has to be quick. Here's an demonstrative game between GM Federico Perez Ponsa and IM Dimitry Stets. 
You can see that at this level, a single inaccurate mistake can cost the game. Black's g5-g4 saved the day, and under pressure white faltered.
Thanks for reading! I hope you enjoyed this, and we'll continue with 13. Rc1 next time.