The opening, explained move by move

There are only three things happening in every opening ever played: the fight for the centre, the race to develop, and the question of where the king will be safe. Every move in this course is one of those three, or a preparation for one of them.

The rules the whole course is built on

1. Fight for the centreA piece in the middle of the board touches more squares than the same piece on the edge. Pawns on d4/e4 (or d5/e5) take squares away from the opponent's pieces before those pieces even move. You can occupy the centre with pawns, or control it from a distance with pieces. Both work, and the difference between those two philosophies is the difference between the Queen's Gambit and the King's Indian.
2. Develop with purpose, knights before bishopsGet a new piece into the game every move. Knights first, because a knight's best square is usually obvious on move two while a bishop's depends on where the pawns end up. Never move the same piece twice in the opening unless there is a concrete reason: every repeat move is a free move for your opponent.
3. Castle early, usually before move tenThe king in the centre is the single most common cause of a lost game below master level. Castling also connects the rooks, which is how they enter the game at all.
4. Do not bring the queen out earlyAn early queen looks aggressive and simply loses time. Every developing move your opponent makes chases her, and you end up three moves behind with nothing to show for it.
5. Attack a pawn chain at its baseA chain of pawns is only as strong as the pawn holding it up. This one idea explains the French Defence, the King's Indian, the Advance Caro-Kann and half the positions in this course.
6. Every advantage is paid forSpace costs flexibility. Extra material costs time. A strong bishop costs a weak colour complex. When you see a move that looks free, look for the bill.

How to use this course

Pick one opening for White with 1.e4 or 1.d4, one answer to 1.e4, and one answer to 1.d4. That is your whole repertoire: three openings, not twelve. Step through each variation until you can predict the next move before you play it, then read the plan card underneath and try to explain the position out loud in your own words.

Two ways to work through a line, and the switch sits above the board. Read walks you through it; play a move on the board at any point and the course answers that move. Drill hides what comes next and asks you for it, with a hint ladder and a score.

Do not memorise past the point where you understand. A player who knows six moves and the reason behind them beats a player who knows twenty and no reasons, because the second player is lost the moment the opponent deviates, and the opponent always deviates.

The vocabulary you need

Tempo

One move's worth of time. If your opponent has to move a piece twice because you attacked it, you have won a tempo. Gambits are the purchase of tempi with material.

Development

How many of your pieces are off their starting squares and doing something useful. Rooks on their original squares do not count.

Pawn structure

The skeleton of the position. Pieces move; pawns mostly do not. That is why the structure determines the plan: it is the part of the position you cannot take back.

Outpost

A square in or near the enemy camp that cannot be attacked by an enemy pawn. A knight on an outpost is often worth more than a rook.

The bishop pair

Having both bishops when your opponent has one bishop and a knight. Worth roughly half a pawn, and much more in open positions where the bishops have long diagonals.

Bad bishop

A bishop trapped behind its own pawns on the same colour squares. The French Defence's light-squared bishop is the most famous example in chess.

Prophylaxis

Stopping your opponent's idea before they have played it. Moves like h3 and a3 look like a wasted tempo and are often the strongest move on the board.

Minority attack

Advancing two pawns against three to force a weakness. The defining plan of the Exchange Queen's Gambit.

Isolated queen's pawn (IQP)

A d-pawn with no friendly pawns beside it. A weakness in the endgame and an attacking engine in the middlegame, so whoever has it must attack now.

ECO code

The catalogue number for an opening (A00–E99), used by every database and book. Useful for looking up more once you have chosen a repertoire.

When they play something else

Press They deviated above the board, or simply play their move on the board, and the course answers the move they actually played. Every answer carries the mark a player already reads:

• ??BlunderThere is a refutation, and here it is.
• ?!InaccuracyPlayable, but it costs something lasting.
• =PlayableA real move. Nothing to refute, so develop and carry on.

Most deviations are the third kind. A trainer that answers every one of them with a red cross teaches you to hunt for refutations that were never there.

Under the board is what Stockfish makes of the position you are looking at, and under the note is what the move just played did to that number. Positive is good for White, negative for Black, and a pawn is worth about 1.00, so +0.30 is a pleasant game and +1.50 is usually decisive at club level. Read it as a second opinion, not as an instruction: the engine will happily tell you a position is level in a way no human could hold over the board.

Reading the board cues

Every move in this course is annotated the way a good coach or a book like Chernev's Logical Chess: Move by Move would, covering what each move does as well as what was played. Under each move you'll see an On the board line telling you what the move attacks, defends, and which squares it controls. It is generated by a chess engine, so it's always accurate. Turn Arrows on, under the board, to see the same information drawn on the pieces:

• A green arrow is the move just played.
• A red arrow means the moved piece attacks an enemy piece on that square: a capture or a threat.
• A bright red arrow is a check.
• A blue arrow means the move defends one of your own pieces that was under attack.
• A dashed amber ring marks a key central square the piece now controls. That is the quiet, positional part of a move.

The aim is Fine's and Chernev's: once you can see why a move is played (what it hits, what it guards, what it fights for), you stop memorising and start understanding, and you can find reasonable moves even when your opponent leaves the book.

Reading the notation

Files are lettered a–h from White's left, ranks are numbered 1–8 from White's side. Pieces are K (king), Q (queen), R (rook), B (bishop), N (knight); a pawn move is written with no letter. Nf3 means a knight moves to f3, exd5 means the e-file pawn captures on d5, O-O is castling kingside and O-O-O is castling queenside. A move written 3...Bb4 is Black's third move; 3.Bb4 would be White's.