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Mate in 3: queen to d6 (a3·3)

Shuffle Rating 1630Theme: Chess960 twist: use the unusual starting setup of the pieces.
White to move — find the best continuation

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The tactical motive

Chess960 twist: use the unusual starting setup of the pieces.

Mate in 3: a forced sequence that ends in checkmate.

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.

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 c2, queen a3, rook a1 f1, bishop c6, knight d2, pawn a2 b2 h2 d3 e3 g3 c4.

Black: king d8, queen d6, rook g8, bishop f7, pawn g4 f5 h5 a7.

13 white and 8 black pieces are on the board; the puzzle position arises after move 21.

The position in numbers

White are ahead by 11 points of material (32 against 21; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.

The white king stands on c2, the black king on d8.

It is White to move on move 21, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.

White keeps 7 pawns, Black 4. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: f.

The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.

Solution & explanation

Main line

21. Qxd6+ Kc8 22. Qd7+ Kb8 23. Qb7#

Why it works

  • Great move! queen to d6 keeps the pressure (#2).
  • Spot on — queen to d7 (#1).
  • Precise: queen to b7 is the top choice (#).
  • The line ends in a forced mate in 3.
  • If instead Kc8, then Qd7+ and you win the queen.

Move by move

  • 21. Qxd6+ — queen to d6 (capture) with check
  • Kc8 — king to c8
  • 22. Qd7+ — queen to d7 with check
  • Kb8 — king to b8
  • 23. Qb7# — queen to b7 and it is checkmate

Types in this puzzle

Ladder mate

Two heavy pieces climb line by line, cutting off every retreat.

The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.

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.

Counter-strike

Don't defend — answer the threat with a bigger one.

The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.

About this position

These pieces come from starting position #619.

SP-619 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.

The king starts on d1, the rooks on a1 and f1, the queen on c1.

The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.

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: h2.

The setup belongs to the ThroneGuard family; read right to left it becomes position 241.

The engine's main line opens with d3.

Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 45, 400 000 000 nodes).

Explore position #619

Provenance

Mined from the project's engine self-play games.

Pack 012 · SP-619

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