Calculation: from candidate moves to the final position
Calculating means playing the moves in your head, yours and your opponent’s, before you touch a piece. Here is a four-step method for doing it at the board, worked through on two puzzles from real games.
What it means to calculate
To calculate is to follow a line of moves in your head: your move, your opponent’s reply, your next move, and so on, until you can say who stands better at the end. You cannot do it for every move of a game, and you do not need to. You calculate when something forcing is on the board: a check, a capture, a piece under attack.
A tactic is often missed not because the player did not know it, but because they stopped looking too early. They found a good move, imagined the reply they hoped for, and played. The method below makes you look at the moves you would rather not see. Our article on finding a mate in two starts with the first habit, checks, captures and threats; this one goes further, to any position where the moves are forcing.
How to calculate in chess: four steps
1. List your candidate moves
Candidate moves are the moves worth calculating. Before you go deep into one of them, list them all, the most forcing first: checks, then captures, then threats. Forcing moves leave your opponent few replies, so they are the quickest to calculate to the end.
Before you list yours, ask what your opponent’s last move threatens. A piece that is attacked can move, be defended, or be left where it is while you make a bigger threat. That third option is sometimes the best one, and it is the easiest to forget.
Do not play the first good move you find. Find two or three, then compare them.
2. Find your opponent’s best reply
For each candidate, sit on the other side of the board and look for the best answer, not the one you hope for. Look at your opponent’s forcing moves first: every check, every capture, every move that attacks one of your pieces. A capture you had not seen, or a check that comes before your threat, is what usually breaks a line.
If one reply refutes your move, the candidate is out, however good the rest looks. If several replies are possible, you need an answer to each of them.
3. Go to the end of the line
Keep going until the position is quiet: no more checks, no more captures, no piece left hanging. Only then judge it. Count the material, look at both kings, and look for a piece that is still loose. Then compare your candidates by the positions they end in, not by their first move.
4. The blunder check
Before you play, look once more at the board as it will be after your move, and take your opponent’s side: what are their checks, their captures, their threats? It takes a few seconds and catches the reply you forgot in step 2. Do it most of all when the move looks obvious.
First example: seven checks, one that works
There is no time for a slow move: the queen is attacked, and the white queen on h7 is close to the black king. So the candidates are the checks, and Black has seven: 1…Rh4+, 1…Qh4+, 1…Qh3+, 1…Qxf3+, 1…Qh2+, 1…Qg2+ and 1…Qxg1+.
Step 2 removes most of them at once. 1…Qh3+ is met by 2.Qxh3, 1…Qh2+ by 2.Kxh2 and 1…Qg2+ by 2.Rxg2: three ways to give the queen away. 1…Qxg1+ 2.Kxg1 gives it for a rook. 1…Qxf3+ wins a pawn with check, but after 2.Rg2 Black has no good follow-up and is still a bishop down: White is winning.
Two moves are left, and they look alike: the queen or the rook to h4. Step 3: go to the end of each. After 1…Qh4+ 2.Qxh4 Rxh4+, the queens are off and Black is still a bishop down. After 1…Rh4+, White’s only legal reply is 2.Qxh4, and 2…Qxh4+ takes the queen with check. Black has given a rook for the queen and is winning. Same squares, same captures: only counting at the end of each line tells them apart.
Second example: answer a threat with a bigger one
Step 1 starts with the threat: the queen on d6 is attacked. The candidates are to move the queen, for example 1…Qe7, to take the rook, 1…Qxc6, or to take the knight, with the pawn, 1…fxe5, or with the knight, 1…Nxe5.
Step 2 for each. 1…Qxc6 loses the queen to 2.Nxc6. 1…fxe5? wins a knight but forgets the queen: after 2.Rxd6 cxd6 3.dxe5, Black has a rook and a knight for the queen, the black centre pawns start to fall, and White is winning. 1…Qe7 saves the queen, but White keeps a clear advantage.
1…Nxe5! is different: the knight takes on e5 and attacks the white queen on d3 at the same time. Now both queens are attacked. White’s best reply is 2.Rxd6, and after 2…Nxd3 the queens are gone and Black has won the knight. Taking the knight with a pawn is worse: after 2.dxe5, for example, 2…Qxc6 takes the rook, and Black is a whole rook up.
Step 4, the blunder check, looks at White’s checks too. There is only one, 2.Qxh7+, and after 2…Kxh7 Black is still winning.
Seeing the board in your head
The hardest part of calculating is seeing a position that is not on the board. In the second example, you must see, two moves ahead, that the knight on e5 still attacks d3 once your own queen has gone. The pieces that have moved in your head are the ones you lose track of: a piece that has left a square no longer guards it, and a line that was blocked may now be open.
This visualisation gets better with practice. Say the line to yourself, move by move, and at the end describe the position: where the kings are, which pieces are loose, what has changed. If you cannot see it clearly, the line is too long for now: stop where you can still see the board and judge the position there.
How to train your calculation
The best practice is puzzles solved without moving the pieces. Write the whole line on paper, with your opponent’s best reply, before you look at the solution. When you get one wrong, find the step that failed: a candidate you never listed, a reply you did not see, or a final position you misjudged. Our article on puzzles on paper or on screen explains why paper makes you calculate.
300 Chess Puzzles has thirty puzzles in each of its ten themes, from about 600 to 1800 Elo, and most of its solutions also show the tempting move that fails and the reply that refutes it: steps 2 and 3, written out. You can start with the twenty free puzzles of our Lichess study, and The Knight’s Notebook brings you sixty puzzles a month at your level.
In your games, use the method when a check, a capture or a threat is on the board, and play slower games, where you have time for all four steps. If you feel you have stopped improving, our article on what to do when you are stuck has more advice.