Mate in 3: queen to e6 (e1)
c9-24995naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Mate in 3: a forced sequence that ends in checkmate.
A fork made possible by the Chess960 piece placement.
Difficulty 1630 ShuffleRating — for advanced tacticians.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king c1, queen e1, rook b2 d3, bishop h2 h5, knight f1, pawn a2 d2 f2 b3 g6.
Black: king c8, rook f4, bishop g2 h8, knight b6, pawn h3 a7 b7 c7 e7 h7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 13 points of material (33 against 20; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on c8.
It is White to move on move 21, with 37 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c, e, h.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Qe6+ Nd7 22. Qxd7+ Kb8 23. Qd8#
Why it works
- Best move. queen to e6 is exactly what the engine plays (#2).
- Spot on — queen to d7 (#1).
- Precise: queen to d8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Nd7, then Qxd7+ and you win the knight.
Move by move
- 21. Qe6+ — queen to e6 with check
- Nd7 — knight to d7
- 22. Qxd7+ — queen to d7 (capture) with check
- Kb8 — king to b8
- 23. Qd8# — queen to d8 and it is checkmate
Types in this puzzle
Back-rank mate
The king is locked behind its own pawns — a heavy piece strikes the last rank.
The back-rank mate strikes a king locked behind its own unmoved pawns when a rook or queen crashes onto the last rank. The signs: no escape hole in front of the king, and the back rank guarded by a single piece or by nobody at all. Often that lone guard is deflected or traded off first, and only then comes the invasion. In your own games, make luft in time — one pawn move prevents a sudden catastrophe.
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Mate in 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
About this position
These pieces come from starting position #351.
SP-351 · BastionScout — Off-centre king plus a rim knight (a/h): 168 positions carry this shape.
The king starts on c1, the rooks on b1 and e1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 320.
The engine's main line opens with f4.
Morozov Balance Index: 83 of 100 — class A — most balanced. Engine evaluation of the starting position: +16 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #351Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-351
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