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Openings › Mate in one › November 2025 › Exercise 1 of 4

Mate in one: Black to move (exercise m1-b98aa067ac)

Black to move and mate in one. In this position Black can give checkmate with one move. The position comes from a rated Lichess game of November 2025.

Last move: 35.Kh1 (White's king from h2 to h1); its two squares are marked on the board.

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Pick a piece, then its square. Keyboard: Tab to the board, arrow keys to move, Enter or Space to pick.

Hint 1: which piece?

Look for a rook move.

Hint 2: which square?

A mating move goes to a1 or h3.

Show the solution

Two moves give checkmate:

  1. Ra1# (a3 to a1). After this move, the black rook on a1 gives check to the white king on h1, and White has no legal move: checkmate. The white king on h1 has no safe square to go to (g1, g2 and h2). g1 is covered by the black rook on a1 and the black rook on g2. h2 is covered by the black rook on g2. The king may not take the black rook on g2: the black bishop on e4 guards g2. No white piece can capture the black rook on a1. No white piece can move to b1, c1, d1, e1, f1 or g1 to block the check.
  2. Rh3# (a3 to h3). After this move, the black rook on h3 gives check to the white king on h1, and White has no legal move: checkmate. The white king on h1 has no safe square to go to (g1, g2 and h2). g1 is covered by the black rook on g2. h2 is covered by the black rook on g2 and the black rook on h3. The king may not take the black rook on g2: the black bishop on e4 guards g2. No white piece can capture the black rook on h3. No white piece can move to h2 to block the check.

Our code tried every legal move of Black in this position: these are the only moves that give checkmate.

The position as text

Where this exercise comes from

The position comes from a rated game in our sample of the Lichess open database (CC0 1.0), from the monthly file of November 2025. From a game that began with the Queen's Gambit Declined. In that game Black gave checkmate with the next move. We show no player names and no link to the game. Our code tried every legal move of the position and lists every move that gives checkmate; the list, the hints and the explanations are checked again each time the site is built. How the exercises are chosen: Mate in one and How it works.