Mate in 3: pawn to a8
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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 d1, rook h1 a4, bishop g2, knight e4, pawn c2 d2 b3 d3 f4 a7.
Black: king c8, queen g7, rook g8, bishop b2, knight f5, pawn g4 e6 h6 d7.
11 white and 9 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
Black are ahead by 2 points of material (22 against 24; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on c8.
It is White to move on move 29, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: e, g, h.
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
29. a8=Q+ Kc7 30. Ra7+ Kb6 31. Qb7#
Why it works
- Great move! pawn to a8 keeps the pressure (#2).
- Spot on — rook to a7 (#1).
- Precise: queen to b7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kc7, then Ra7+ and you win the pawn.
Move by move
- 29. a8=Q+ — pawn to a8 with check
- Kc7 — king to c7
- 30. Ra7+ — rook to a7 with check
- Kb6 — king to b6
- 31. 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.
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
About this position
These pieces come from starting position #274.
SP-274 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
The king starts on d1, the rooks on c1 and g1, the queen on h1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 583.
The engine's main line opens with g4.
Morozov Balance Index: 55 of 100 — class B — balanced. Engine evaluation of the starting position: +25 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #274Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-274
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