Winning blow: king to b1 (c1·31)
c9-26169naming 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 1250 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 c1, queen f3, rook a1 e1, knight g1, pawn c2 d2 f2 b3 e3 a5.
Black: king e7, queen f6, rook e8, knight e2 e6, pawn h4 b6 a7 c7 d7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
White are ahead by 2 points of material (28 against 26; 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 e7.
It is White to move on move 16, with 5 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 6 pawns, Black 6. Files fully open (no pawns of either colour): g — natural highways for the rooks and queen. Half-open for White: 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
16. Kb1 Nxg1 17. Qxf6+ Kxf6 18. Rxg1
Why it works
- Great move! king to b1 keeps the pressure (+3.8).
- Well found: queen to f6 (+4.2).
- Strong! rook to g1 is the sharp choice (+4.3).
- You reach a winning position (+4.3).
- If instead Nxg1, then Qxf6+ and you win the queen.
Move by move
- 16. Kb1 — king to b1
- Nxg1 — knight to g1 (capture)
- 17. Qxf6+ — queen to f6 (capture) with check
- Kxf6 — king to f6 (capture)
- 18. Rxg1 — rook to g1 (capture)
Types in this puzzle
Zwischenzug
Before the obvious recapture — an in-between move that wins more.
A zwischenzug means refusing the obvious reply — usually a recapture — and playing a stronger move with tempo first. Typically it is a check or a deadly threat the opponent must answer, after which you calmly take what was hanging anyway. The sign: inside a sequence of exchanges you own a check or a threat that will not run away. Whenever a line looks forced, ask what poison you can slip in between the moves.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
Defensive exchange
Trade off the attacker — the storm dies with it.
The defensive exchange: your opponent's attack runs on one specific piece — trade it off, and the storm dies down. Find the "engine" of the attack, the piece without which the mating threats stop working: usually the queen or an invading knight. Offer the trade even at a small cost — your king breathes, and the material comes back later. The mistake is greedily dodging the exchange and getting mated a pawn up.
About this position
These pieces come from starting position #835.
SP-835 · 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 b1 and e1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 115.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 55 of 100 — class B — balanced. Engine evaluation of the starting position: +25 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #835Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-835
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