Mate in 3: rook to b7 (e7)
c9-26917naming 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 a2, rook e7, bishop f2 d3, pawn b2 d4 h4 f5 g5.
Black: king a5, rook f8 g8, bishop h8, pawn d5 h5 c6 b7.
9 white and 8 black pieces are on the board; the puzzle position arises after move 41.
The position in numbers
Black are ahead by 1 points of material (16 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a2, the black king on a5.
It is White to move on move 41, with 33 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): a, e — natural highways for the rooks and queen. Half-open for White: c.
White hold the bishop pair, an edge in open lines. The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
41. Rxb7 Bxd4 42. b4+ Ka4 43. Bc2#
Why it works
- Great move! rook to b7 keeps the pressure (#2).
- Spot on — pawn to b4 (#1).
- Precise: bishop to c2 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Bxd4, then b4+ and you stay on top.
Move by move
- 41. Rxb7 — rook to b7 (capture)
- Bxd4 — bishop to d4 (capture)
- 42. b4+ — pawn to b4 with check
- Ka4 — king to a4
- 43. Bc2# — bishop to c2 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.
Breakthrough
A pawn sacrifice tears the chain open and lets a passer through.
A breakthrough is a pawn sacrifice that rips the opponent's chain open and creates an unstoppable passer. Look for it where the pawns are locked against each other: often two pawns are given up so the third one slips through. Check the square rule — can the enemy king catch the new passer? If not, sacrifice with confidence; the classic error is breaking through while his king stands right there eating everything.
About this position
These pieces come from starting position #854.
SP-854 · RampartGuard — A b- or g-file king and two knights on inner files (b–g).
The king starts on b1, the rooks on a1 and e1, the queen on h1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 102.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 51 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +26 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #854Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-854
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