Attack on the uncastled king: king to d1 (c1·12)
c9-15905naming 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.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1950 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.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
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, rook f1 d7, bishop b6 e6, knight e1, pawn a2 h2 f4.
Black: king c8, rook f5 a8, bishop c3, knight e2 e8, pawn g6 b7 e7 h7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
Black are ahead by 1 points of material (22 against 23; 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 19, with 3 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 3 pawns, Black 4. Files fully open (no pawns of either colour): c, d — natural highways for the rooks and queen. Half-open for White: b, e, g.
White hold the bishop pair, an edge in open lines. 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
19. Kd1 Nc7 20. Rxc7+ Kd8 21. Rc8#
Why it works
- Sensible development: king to d1.
- Well found: rook to c7 (#1).
- Strong! rook to c8 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Nc7, then Rxc7+ and you win the knight.
Move by move
- 19. Kd1 — king to d1
- Nc7 — knight to c7
- 20. Rxc7+ — rook to c7 (capture) with check
- Kd8 — king to d8
- 21. Rc8# — rook to c8 and it is checkmate
Types in this puzzle
Double-check mate
Double check leaves only king moves — and there are none.
The double-check mate ends the game with check from two pieces at once, leaving the king with nothing. Neither capturing nor blocking works against a double check — only a king move, and here there is none. Look for a discovered check where the front piece checks too: it may even land on a defended square with total impunity. That is why the double check crowns so many of the most beautiful sacrificial combinations.
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.
Two-bishop mate
The bishop pair sweeps two adjacent diagonals — the king has nowhere to hide.
The two-bishop mate rakes two adjacent diagonals: one bishop mates while the other seals off the escape squares. The bishops complement each other perfectly — living on opposite colors, together they cover an unbroken strip of the board. The pattern usually appears at the edge or in the corner where the king was pressed beforehand. Treasure the bishop pair until the attack comes — on an open board two adjacent diagonals become a solid wall.
About this position
These pieces come from starting position #703.
SP-703 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on c1, the rooks on a1 and f1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 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: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 448.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #703Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-703
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