Winning blow: knight to c3 (e2·2)
c9-20719naming 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 1290 ShuffleRating — club-player level.
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 d1, queen b1, rook a1 f1, bishop e4 a5, knight e2 b7, pawn b2 h2 g3 f4 d6.
Black: king b5, queen b8, rook e7 a8, bishop h8, pawn c5 e6 g6 a7 f7 h7.
13 white and 11 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 8 points of material (36 against 28; 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 b5.
It is White to move on move 17, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a, c, e.
White hold the bishop pair, an edge in open lines. 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
17. Nc3+ Bxc3 18. bxc3+ Kc4 19. Ra4#
Why it works
- Best move. knight to c3 is exactly what the engine plays (#2).
- Spot on — pawn to c3 (#1).
- Precise: rook to a4 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bxc3, then bxc3+ and you stay on top.
Move by move
- 17. Nc3+ — knight to c3 with check
- Bxc3 — bishop to c3 (capture)
- 18. bxc3+ — pawn to c3 (capture) with check
- Kc4 — king to c4
- 19. Ra4# — rook to a4 and it is checkmate
Types in this puzzle
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.
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
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 #603.
SP-603 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on d1, the rooks on a1 and f1, the queen on b1.
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 257.
The engine's main line opens with d3.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #603Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-603
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