# Does this knight and rook mating pattern have a name, or has it occurred before?

``````[fen "5k2/8/1R6/5r2/P7/1P4P1/6KP/5n2 b - - 0 40"]
``````

With black to move, remarkably it's mate in 2 (at first glance, it looks like black may struggle to even draw). It occurred in a recent LiChess game of mine. It looks like the kind of position that might occur in a composed puzzle because it contains the precise material required to checkmate.

Question: Does this knight and rook mating pattern have a name, or has it occurred before?

When there's a mating pattern involving so little material (just the rook and knight, no king), I feel it might be worthwhile studying it in its own right. The knight and rook could be on multiple other squares and still achieve essentially the same mate.

• Not sure if it has a name, but that is one of the most beautiful mates-in-two I have ever seen! Very nice! – Brandon_J Apr 19 '19 at 3:11

I believe that that is called “Anatasia Mate,” according to Wikipeda.

Here is an Anatasia checkmate:

``````[FEN "8/4N1pk/8/7R/8/8/3K4/8 w - - 0 1"]
``````

And here is the checkmate from your game:

``````[FEN "5k2/8/1R6/7r/P7/1P2n1PK/7P/8 w - - 0 1"]
``````

Even though White king has an extra pawn by it, your checkmate is still pretty much an “Anatasia’s Mate.”

• The final position looks like an Anastasia's Mate, although shifted one row from its typical position, and reached by non-traditional means, but from the position originally posted, the game could have ended with two other mates: a back-rank mate assisted by the knight to take away one flight square, or what looks like an Arabian mate shifted one column and assisted by one of the white pawns taking a flight square from its own king. – itub Apr 19 '19 at 12:13

That is a nice problem, with rook and knight mating a king at the edge, with one square blocked. Here's a helpmate problem which shows more examples of that phenomenon:

``````[Title "Forsberg, Revista Romana de Sah, 1935. h#2. b) bRa6 c) bBa6 d) bNa6 e) bPa6"]
[StartFlipped "0"]
[fen "8/8/q7/8/1R4K1/k2N4/8/8 b KQkq - 0 1"]

1... Qf6 2. Nc5 Qb2 3. Ra4#
``````

My analysis is based on that by John Nunn, Solving in Style, prob. 133. White's king is too far away to participate in the mating-net (though it is accurately placed to avoid dual solutions). So White must mate with rook and knight alone. Rook and knight can mate, but only if bK is in a corner. With only 2 Black moves, this corner must be a1, but this entails wNc3, which the knight can't reach in two moves. Therefore Black must block one square in bK's field, and this is where the unit on a6 comes in. The 5 choices of unit lead to 5 different mating nets.