Principles that survive move ten

Between 1000 and 2000, almost nobody loses in the opening because of theory. They lose because they broke a principle on move six, or because their opponent played something odd and they had no idea what to do without a memorized line. Both problems have the same cure.

The six

1. A pawn in the centre. e4 or d4 (or e5, d5, c5 as Black) on the first move or two. It claims space, opens lines for two pieces, and gives you something to defend and build behind.
2. Knights and bishops out before anything else. Four minor pieces, four moves. Each to a square where it does something: a knight toward the centre, a bishop on a diagonal that points somewhere.
3. Castle by move ten, or earlier if the centre could open. The king safety article says why.
4. Do not move the same piece twice before the others are out, unless a tactic forces it. Every second move of a developed piece is a whole piece the opponent gets for free.
5. Do not bring the queen out early. It becomes a target, and every attack on it is a free developing move for the opponent.
6. Connect the rooks, then decide on a plan. When the back rank has nothing between the rooks, the opening is over. Now think.

What to do when they play something strange

This is the situation the principles are for. The opponent plays 1.b4, or 2.Qh5, or an early ...a6 and ...b5. You have no line. Good: you have something better.

• Do not punish it. Odd moves are rarely losing; they are usually just slower. Trying to refute them by force is how you end up behind in development yourself.
• Play the six. Centre pawn, pieces out, castle. By move ten you will have a normal position and a small lead in development, and the opponent will be the one who has to find something.
• Look at what the odd move weakened. 2.Qh5 leaves the queen loose; ...b5 leaves c6 and a5 weak. One idea aimed at that weakness is enough. You do not need three.

What the principles do not tell you

They get you to a playable middlegame. They say nothing about which middlegame you want. That is the next article: a repertoire from your own games, which is about picking a small number of structures, learning one plan in each, and never again arriving at move fifteen with no idea what to do.

The tell

It is move eight and you have moved a piece twice, or your queen is out, or your king is in the centre with a pawn break available. Any of those is a principle broken, and the position will usually tell you which.

The habit

At move ten, count: centre pawn, four minor pieces developed, king castled, rooks connected. Each missing item is the move to play next.