Mate in 3: rook to b6 (b8)
c9-23855naming 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.
Mate in 3: a forced sequence that ends in checkmate.
Difficulty 1630 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.
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 e1, rook g5 b8, bishop h1, knight f5, pawn a3 d3 e3 g3 c4 h4.
Black: king e6, rook h6 d7, knight h5, pawn d5 f7.
11 white and 6 black pieces are on the board; the puzzle position arises after move 39.
The position in numbers
White are ahead by 7 points of material (22 against 15; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e6.
It is White to move on move 39, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 2. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: f.
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
39. Rb6+ Rd6 40. Rxd6+ Ke5 41. d4#
Why it works
- Best move. rook to b6 is exactly what the engine plays (#2).
- Spot on — rook to d6 (#1).
- Precise: pawn to d4 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rd6, then Rxd6+ and you win the rook.
Move by move
- 39. Rb6+ — rook to b6 with check
- Rd6 — rook to d6
- 40. Rxd6+ — rook to d6 (capture) with check
- Ke5 — king to e5
- 41. d4# — pawn to d4 and it is checkmate
Types in this puzzle
Pawn mate
The humblest soldier delivers the final blow.
The pawn mate lets the humblest soldier land the final blow. It happens to a king stuck among its own and enemy pieces: the pawn strikes diagonally from one square away and there is nowhere left to run. The sign: the squares around the king are covered or occupied, and your pawn stands one step from striking distance. Never write pawns out of your attack — their blows are the cheapest and therefore the most humiliating.
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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #119.
SP-119 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
The king starts on f1, the rooks on d1 and g1, the queen on b1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 trade places.
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 BastionScout family; read right to left it becomes position 834.
The engine's main line opens with c4.
Morozov Balance Index: 97 of 100 — class A — most balanced. Engine evaluation of the starting position: +7 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #119Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-119
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