Chess960 tactic on b1
c9-10734Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Mate: a forcing sequence that ends the game — the king has no escape.
Mate in 4: a forced checkmate in four moves — every reply is covered.
Difficulty 2120 ShuffleRating — expert level — few solve it at first try.
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 is a forced mating attack. Start from the enemy king: which of its squares are already covered, and which move takes away the rest while keeping the king in check? Forcing moves — checks and captures — are what turn an attack into mate.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
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, queen a7, rook d4, bishop c4, knight c5, pawn a2 c3 f5.
Black: king c8, queen b1, rook e8, knight g5, pawn h7.
8 white and 5 black pieces are on the board; the puzzle position arises after move 38.
The position in numbers
White are ahead by 5 points of material (23 against 18; 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 c8.
It is White to move on move 38, with 2 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 1. Files fully open (no pawns of either colour): b, d, e, 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
38. Kxb1 Re1+ 39. Kc2 Rc1+ 40. Kxc1 Ne4 41. Ba6#
Why it works
- Great move! king to b1 keeps the pressure (#3).
- king to c2 develops smoothly.
- Precise: king to c1 is the top choice (#1).
- Best move. bishop to a6 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Re1+, then Kc2 and you win the queen.
Move by move
- 38. Kxb1 — king to b1 (capture)
- Re1+ — rook to e1 with check
- 39. Kc2 — king to c2
- Rc1+ — rook to c1 with check
- 40. Kxc1 — king to c1 (capture)
- Ne4 — knight to e4
- 41. Ba6# — bishop to a6 and it is checkmate
Types in this puzzle
Mate in 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
Remove the defender
Capture the guard first — then take what it protected.
Removing the defender is the straightforward plan: capture the guard first, then take what it guarded. Unlike deflection, the defender is not lured away — it is traded off or destroyed on the spot. Stare at the target you crave and ask who defends it, and whether that defender can be profitably eaten. Count the whole capture sequence, not just the first move — the trade must pay off at the end.
King evacuation
The king walks out of the danger zone on its own feet.
King evacuation: when the shelter collapses, the king walks out of the attack on his own feet — sometimes across half the board. A series of precise king moves carries him out of the firing zone, and the enemy attack dissolves. The signs: no direct defense works, but there is a route over unattacked squares to a quiet corner. Calculate the entire journey in advance — a king stranded halfway usually dies there.
About this position
These pieces come from starting position #836.
SP-836 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on a1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
The pawn on e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 126.
The engine's main line opens with f4.
Morozov Balance Index: 59 of 100 — class B — balanced. Engine evaluation of the starting position: +24 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #836Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-836
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