A mate in 3 is three of your moves and two of your opponent's, ending in checkmate whatever they do. That is too many positions to check at random, so these puzzles train the skill that matters in real games: choosing which lines to calculate and seeing them through to the end. Every puzzle comes from a real game and is matched to your puzzle rating.
With one move to find, you can test every check. With three, the number of possible lines grows too fast for that. Strong solvers do not calculate more lines; they calculate the right ones. The filter is forcing moves: checks first, then captures, then threats that demand an answer. A line made only of checks is the easiest to see through, because each check leaves the opponent very few replies.
Mate in 3 puzzles are a good place to learn this, because the goal is fixed and the answer is certain. In a game you rarely know whether a mate exists. Here you do, so every minute goes into finding it rather than wondering.
First study the king: its free squares, its defenders, and the lines leading to it. Then list your forcing candidate moves and pick the one that leaves the opponent fewest replies. Follow it one move at a time, and at each step find their most stubborn defence, not the obvious one.
Keep a clear picture of where every piece stands after each move. Most calculation errors are not bad ideas; they are a piece remembered on the square it left two moves ago. If the board in your head gets blurry, go back to the start and walk the line again rather than guessing the end.
Finally, check the final position properly. It should be mate, with every escape square covered and no capture or block available. A line that ends in a big material win is not a mate in 3, and the puzzle will not accept it.
Longer mates reuse a small set of ideas. A king hunt uses checks and sacrifices to drag the king out of its shelter into open ground. A smothered mate uses a knight against a king surrounded by its own pieces, often after a sacrifice forces a piece onto its last free square. A line clearance gives up a piece so that a rook, bishop or queen can reach the king along the path it was blocking. And many mates are two pieces working together: queen and knight, rook and bishop, or two rooks on the seventh and eighth ranks.
Recognising which of these is in front of you shortens the calculation, because you already know roughly where the king will be mated.
Calculating only your own moves is the big one. Each of your moves must work against every reply, and the reply that breaks a line is often a check or a counter-sacrifice you did not consider. The other common mistake is moving too early: playing the first move because it feels right and hoping the rest will appear. In the trainer, a wrong move counts the puzzle as a miss, even if you then find the mate.
Set yourself one rule: no move until you have seen mate against every reply. Take as long as you need, because there is no clock here. After each of your moves the opponent's reply is played on the board, which lets you check whether your calculation matched. Once you solve a puzzle, the full line appears beside the board.
If three moves is too many for now, build up through mate in 1 and mate in 2. For the opposite skill, fast recognition under pressure, use Puzzle Storm.
For mixed tactics at your level, use Puzzle Training. To drill one fixed set of positions until the ideas are instant, try the Woodpecker Method. Elo Maxing rates you on each tactical motif and serves the weakest next. To see where calculation goes wrong in your own games, read how to review your chess games.
It adds one more move for each side, which means far more possible lines. The skill it trains is choosing forcing moves and checking every defence.
Yes. After each of your moves, the opponent's reply from the puzzle is played on the board, and you continue from there.
No. Rated puzzles have no clock, so you can calculate as long as you need. Puzzle Storm is the timed mode.
Mate in 3 puzzles accept the moves of the puzzle's own solution line. Only mate in 1 puzzles accept any move that checkmates.