Chess tactics
Mate in 3: Calculate a Forced Checkmate
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A mate in 3 guarantees checkmate by your third move against every legal defence. The solution may begin with a check, sacrifice, or quiet key; what matters is that the mating net holds after the defender's strongest replies.
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Mate in 3: what it is and how it works
Checks, captures, and direct mate threats often limit the opponent's replies and make the tree easier to calculate. A sacrifice may strip the king's shelter or attract it onto a line, but do not assume the continuation is forced: record the legal replies at each ply and check each branch to the stated horizon.
Where mate-in-three gets hard is the quiet move buried inside the sequence — a non-checking move that removes the king's last escape or threatens two mates the defender cannot both stop. To solve cleanly, build the net backward: picture the final mating position, work out which squares must be covered, and find the move order that covers them while staying forcing. Then verify each defensive try runs into mate by move three.
How to spot it over the board
- Begin by examining checks and captures, then include quiet threats when the forcing moves let the king escape.
- Look for an opening sacrifice that exposes or attracts the king, then a forcing follow-up.
- Watch for a quiet move in the middle of the sequence that quietly seals an escape square.
- Verify the line against the opponent's best defence, not just the reply you expect.
A common calculation error
The usual breakdown is calculating one defensive line to mate and assuming the rest work too, only to be refuted by an in-between check or a king flight you never examined. A mate in three must be airtight against every reply. The other mistake is checking aimlessly — throwing checks that drive the king to safety instead of into the net. Each check should reduce the king's freedom.
How hard are these puzzles?
This collection contains 109 mate in 3 puzzles, with a recorded median rating of 1378 and a dataset range from 760 to 2056. Puzzle ratings are estimates produced by results in their source pool; they can change and should be read as a guide for choosing practice, not as an objective measure of difficulty.
- Puzzles tagged
- 109
- Lowest recorded rating
- 760
- Recorded median
- 1378
- Highest recorded rating
- 2056
Mate in 3 puzzles to solve
These positions come from the LibreChess trainer and are ordered by the rating stored in this dataset. Play your candidate move on the board, then compare it with the listed solution and replay the continuation.
Worked example 1 — rated 760
White to move. Find the mate in three, then reveal the solution.
34. Ra1+ 34... Ba2 35. Rxa2+ 35... Ra4 36. Rxa4#Worked example 2 — rated 1180
White to move. Find the mate in three, then reveal the solution.
18. Qd7+ 18... Kf8 19. Qd8+ 19... Rxd8 20. Rxd8#Worked example 3 — rated 1378
White to move. Find the mate in three, then reveal the solution.
26. Nxe7+ 26... Kh8 27. Qh5+ 27... Bh6 28. Qxh6#Worked example 4 — rated 1582
Black to move. Find the mate in three, then reveal the solution.
22... Qxf2+ 23. Rxf2 23... Rxe1+ 24. Rf1 24... Rexf1#Worked example 5 — rated 2056
White to move. Find the mate in three, then reveal the solution.
16. Nf7+ 16... Kc7 17. Bf4+ 17... Kb7 18. Nd8#Keep training by rating
Choose a rating band as a starting point. If the positions are routinely immediate or opaque, move one band up or down; puzzle ratings are pool estimates rather than fixed grades.