| Sneaky: <aw1988> Like in mathematics, it's always hard to say somebody is responsible for something... chess is more of a process of discovery than invention. Here's an example of a double Grimshaw interference:
click for larger viewWhite to play and mate in two. (Loshinsky, 1930)
Scroll down for solution.
. . . . . . . . . Solution:
1. Bb3!!
Creating no direct threats but leaving Black in a state of zugwang, in spite of his wealth of movable pieces. The Grimshaws occur on b7 and g7 here, hence it's a "double grimshaw". For example if 1...Rb7, Black will block his own bishop on a8, allowing 2.Rc6#. But if Black plays 1...Bb7 then he blocks his own rook, allowing 2.Re7#. On g7 another grimshaw interference takes place. On 1...Rb7 the h8-bishop is blocked to allow 2.Qe5#. On 1...Bb7 the h7-rook is blocked to allow 2.Qxf7#. There's even another interference going on: that of the f-pawn. E.g. if 1...Bc6, white has 2.Qg4#, because the bishop blocked the f-pawn. A very famous puzzle.
<Grimshaw vs Novotny interference> For years I puzzled over the difference between a Grimshaw interference and a Novotny interference, but now I think I finally know the difference. In a Grimshaw, it's Black (the losing player) who blocks himself, so that every defense to one mate cuts off another piece to allow a different mate. In a Novotny interference it's White (the winning player) who plunks a piece down on the interference square which curiously cannot be captured due to the same interference problem. Novotny tactics are often breathtaking, because a player will put a piece on a square which can be captured so many ways, and yet it's immune to capture. And it's not a revealed attack--it's pure interference. Puzzles with Novotny solutions often appear so outlandish they look like typographical errors. | 
