Mate in 3: rook to b1 (d1)
c9-25817naming 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.
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, rook a1 d1, bishop g8, knight f4 a6, pawn g2 h2 e4.
Black: king b6, queen e8, rook a8, bishop f5 e7, knight e5, pawn c6 f6 g6 h7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
Black are ahead by 5 points of material (22 against 27; 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 b6.
It is White to move on move 27, with 48 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 4. Files fully open (no pawns of either colour): a, b, d — natural highways for the rooks and queen. Half-open for White: c, f.
Black hold the bishop pair, an edge in open lines. The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
27. Rdb1+ Bb4 28. Rxb4+ Ka7 29. Nc5#
Why it works
- Great move! rook to b1 keeps the pressure (#2).
- Well found: rook to b4 (#1).
- Precise: knight to c5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bb4, then Rxb4+ and you win the bishop.
Move by move
- 27. Rdb1+ — rook to b1 with check
- Bb4 — bishop to b4
- 28. Rxb4+ — rook to b4 (capture) with check
- Ka7 — king to a7
- 29. Nc5# — knight to c5 and it is checkmate
Types in this puzzle
Discovered mate
A piece steps aside — and the one behind it delivers mate.
In a discovered mate the piece that moves is not the one that mates — the long-range piece behind it delivers the blow. The moving piece is completely free: it can land anywhere, ideally stealing the king's last squares or guarding key points. Look for your rook, bishop or queen lined up with the enemy king, with exactly one of your own pieces in between. When choosing the unveiling move, remember its second job — shutting the king's escape door.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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 #805.
SP-805 · RampartScout — A wing-file king (b or g) and at least one corner knight: the rarest of the six families, just 72 positions.
The king starts on b1, the rooks on a1 and g1, the queen on e1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the RampartScout family; read right to left it becomes position 154.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #805Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-805
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