Mate in 3: knight to b3
c9-15547Opens 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.
Difficulty 2170 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.
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.
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 b2, rook d8, bishop d4, knight c5, pawn c2 d2 a3 b4 f4 e6.
Black: king c6, bishop h8, pawn a5 b5 h5 f6 c7 e7 h7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
White are ahead by 7 points of material (17 against 10; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on c6.
It is White to move on move 30, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. 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 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
30. Nb3 Kb7 31. Nxa5+ Ka6 32. Ra8#
Why it works
- Great move! knight to b3 keeps the pressure (#2).
- Spot on — knight to a5 (#1).
- Precise: rook to a8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kb7, then Nxa5+ and you stay on top.
Move by move
- 30. Nb3 — knight to b3
- Kb7 — king to b7
- 31. Nxa5+ — knight to a5 (capture) with check
- Ka6 — king to a6
- 32. Ra8# — rook to a8 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.
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.
Endgame tactic
Tactics live in the endgame too — strike while material is scarce.
Tactics do not retire when the queens come off: forks, pins and double attacks live on in the endgame. With so little material left, every tactical loss is almost always decisive. The signs are the usual ones — undefended pieces, king and piece on one line, a pawn about to promote. Even in a "technical" ending, scan for a shot before every move, both yours and your opponent's.
About this position
These pieces come from starting position #707.
SP-707 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on b1 and g1, the queen on d1.
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, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 435.
The engine's main line opens with b4.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #707Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-707
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads