Winning blow: knight to a5 (b3·7)
c9-22732naming 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.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1700 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.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
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 d8, bishop e1, knight b3, pawn b2 c2 d2 g2 g5 a7.
Black: king b7, queen g6, rook h8, bishop e8 f8, knight h1 c8, pawn e4 h6 c7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
Black are ahead by 8 points of material (21 against 29; 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 b7.
It is White to move on move 24, with 32 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 3. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: e, h.
Black 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
24. Na5+ Kb6 25. a8=Q Qc6 26. Qb8+ Ka6 27. Qdxc8+
Why it works
- Great move! knight to a5 keeps the pressure (#6).
- Well found: pawn to a8 (#5).
- Precise: queen to b8 is the top choice (#4).
- Best move. queen to c8 is exactly what the engine plays (#3).
- You win a piece — the knight.
- If instead Kb6, then a8=Q and you win the pawn.
Move by move
- 24. Na5+ — knight to a5 with check
- Kb6 — king to b6
- 25. a8=Q — pawn to a8
- Qc6 — queen to c6
- 26. Qb8+ — queen to b8 with check
- Ka6 — king to a6
- 27. Qdxc8+ — queen to c8 (capture) with check
Types in this puzzle
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
Promotion
The pawn reaches the last rank and becomes a queen — decisively.
Promotion turns a pawn on the last rank into a queen and rewrites the evaluation on the spot. In tactics the passer rarely walks in for free — usually a sacrifice clears its path. Count the tempi: how many moves does the pawn need, and can the defender stop it in time? And watch the promotion square itself — it must be out of enemy reach or won by force in your combination.
About this position
These pieces come from starting position #746.
SP-746 · RampartGuard — A b- or g-file king and two knights on inner files (b–g).
The king starts on b1, the rooks on a1 and h1, the queen on g1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 405.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 59 of 100 — class B — balanced. Engine evaluation of the starting position: +24 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #746Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-746
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads