Mate in 3: queen to e6 (e4·2)
c9-20269naming 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 1980 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 b1, queen e4, rook e7 h8, bishop f7, pawn b2 g2 h2 f3 d4.
Black: king b6, queen a5, rook d5 a7, bishop e8, pawn b5 a6 f6 g7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 33.
The position in numbers
White are ahead by 1 points of material (27 against 26; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b6.
It is White to move on move 33, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): c, e — natural highways for the rooks and queen. Half-open for White: a.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
33. Qe6+ Bc6 34. Rb8+ Rb7 35. Rexb7#
Why it works
- Best move. queen to e6 is exactly what the engine plays (#2).
- Well found: rook to b8 (#1).
- Precise: rook to b7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bc6, then Rb8+ and you stay on top.
Move by move
- 33. Qe6+ — queen to e6 with check
- Bc6 — bishop to c6
- 34. Rb8+ — rook to b8 with check
- Rb7 — rook to b7
- 35. Rexb7# — rook to b7 (capture) and it is checkmate
Types in this puzzle
Epaulette mate
The king's own pieces flank it like epaulettes — mate comes head-on.
In the epaulette mate the king stands between two of its own pieces — most often rooks — like an officer wearing epaulettes. The side squares are blocked by friends, there is no retreat, and the queen mates head-on from directly in front of the king. The sign: a king on the edge rank with both neighboring squares on that rank occupied by its own pieces. Remember, extra defenders crowding the king can be deadlier than no defenders at all.
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 #920.
SP-920 · BastionScout — The king starts one file off-centre, on c or f, and a knight begins in a corner.
The king starts on c1, the rooks on a1 and d1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the BastionScout family; read right to left it becomes position 45.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 11 of 100 — class D — largest edge. Engine evaluation of the starting position: +42 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #920Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-920
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