Brinkmate: the threat with no answer.

Threatmate, brinkmate, mate

Three words, three different claims about the next move.

• Threatmate 詰めろ tsumero: if the defender does nothing, mate next move. A claim about one reply, the pass. It can usually be defended.
• Brinkmate 必至 hisshi: a threatmate that cannot be defended. A claim about every reply. The game is over unless the defender can mate first.
• Mate 詰み tsumi: a check with no reply at all.

Two basic shapes

Both come from the same idea: take the king’s squares away with a quiet move so that the mating move next turn cannot be answered. Under each diagram the engine has listed every legal reply and the mate that punishes it. Open the list; that is what “no defence” means.

How a threatmate is answered

When the position above is only a threatmate, the defender has four kinds of move. Knowing them is what lets you tell a threatmate from a brinkmate at the board: run through the four, and if none works, it is a brinkmate.

1. Move the king out. Not into the corner. The proverb says the king should run away from the attacking pieces, toward the open side, and a king that steps into the corner turns a threatmate into a brinkmate.
2. Drop a defender. On the mating square itself, or in the line of the piece that would protect the mating piece. In the contrast diagram all three parries are gold drops, and each one either occupies 3b or cuts the dragon off from it.
3. Remove the attacker. Capture the piece that would give mate, or the piece protecting it. A defender who can take the dragon does not need to count anything else.
4. Threaten back. A parry that is itself a threatmate is worth two moves, and a threatmate that is not a parry is worth nothing. Japanese has a name for the good version, tsumero-nogare no tsumero, “the threatmate that escapes a threatmate.” Speed counting is the page for it.

A brinkmate is the position where all four fail. The lists above are those four checked exhaustively, by machine.

Your own king

A brinkmate wins the game only if the opponent cannot mate you first. In a brinkmate problem the attacker’s king is off the board, so the question does not arise; in a game it is the whole question. Before you play the quiet move that makes a brinkmate, look at your own king with the opponent’s pieces and hand, and ask whether it is Z, a shape their checks cannot break.

Japanese has two words for what happens when it is not. A partial brinkmate, bubunteki na hisshi, is a brinkmate against every reply except checks. An effective brinkmate, jijitsujō no hisshi, is one where the defender does have checks, but they run out and change nothing: after the last check the position is a brinkmate again with the same pieces.

Both are common in games and neither appears in problem books, which is why a strong problem solver can still lose an endgame: the book never made them look behind themselves.

How to practise it

Japanese has whole collections of brinkmate problems, and the convention is always the one used here: the attacker has no king, the defender holds every piece not on the board, and the answer is a quiet move after which every reply loses. English has almost none, and the two words that would find them online, hisshi and brinkmate, are the two words this page is built around. The app’s puzzles include brinkmates from real games at your level, and its engine tells you, after every move you play, whether you have made a threatmate or a brinkmate. That feedback is the fastest way to learn to see the difference.