LoA based modelling

 Repertoire books about the opening are geared around the tree of analysis, around variations. But thinking in variations is a quite arduous task. Because the center of gravity of an idea seems to shift through the variations. If you take the idea of an Aurora Australis attack in the Colle Zukertort, then you can reach that attack via quite different move orders. Variations are just too volatile to act as the base for the description of an idea.

It is much more logical to gear the description of an idea around the lines of attack (LoAs). The LoAs shift at a much slower pace during the game. Furthermore, the ideas have a close relation to the LoAs. It is a nice idea to give ideas names, like Aurora Australis, Aurora Borealis, Aurora Polaris and Noah's Ark attack, but you can't give every idea a catchy name.

It would be handy to give each LoA a separate name though. 

Diagram 1. Black to move

r1b2rk1/p1qn1ppp/1p1bpn2/2ppN3/3P1P2/1P1BP3/PBPN2PP/R2Q1RK1 b - -

I dubbed this position as follows:

• Model 1: this position
• LoA 1: diagonal b2 - h8
• LoA 2: diagonal d3 - h7
• LoA 3: file h

Okay, these names aren't very fancy either, but you get the idea. I used model 1 as the base of my investigations. Moves are related to their effect on the LoAs. I investigated the moves with the aid of Stockfish.

Diagram 2. Black to move

The moves by the pieces in the blue circles have no effect on the LoAs of interest. This means you can start the Aurora Australis attack when these pieces move. Let's have a look at the other moves: 

• cxd4: Prevents the clearance move dxc5 from white
• g6: Blocks LoA 2 but creates new holes and hence new LoAs around the black king. Furthermore, it can help as a leverage for white to open files against the black king (new LoAs)
• Rd8, Re8: opens an escape route for the black king
• Be7, Qe8: reïnforces Nf6, hence LoA1
• h6: blocks LoA 3

If black does a move that doesn't influence the LoAs, you can start the Aurora attack, which starts with clearing LoA 1 (the long diagonal) by the moves Nxd7 and dxc5.

In the other cases, white must reinforce LoA 3 by the moves Rf3 or Qf3.

As you can see, this way the thinking about ideas involve the LoAs, while getting rid of the worries that concern the specific variations. You can create the variations at will, whenever you need them.

Notice how every move has a little logic that describes its influence on the LoAs. Take for instance the move Rd8. It opens an escape route for the black king via f8. A walking king means that the LoAs walk along with it.