Novotny

The Novotny appears mainly in composed chess problems. Picture two Black pieces defending along long lines, usually a rook along a rank or file and a bishop along a diagonal. Those two defensive lines cross on one square.

White deliberately places a piece on that intersection. The move blocks both Black lines at once and offers the White piece to be captured. This is a sacrifice: White accepts the loss of a piece because the resulting interference helps achieve the problem's goal, commonly a forced mate.

If either Black line piece captures on the intersection, it removes the White piece but now occupies the critical square itself. It therefore continues to block the other Black piece's line. A rook capture can obstruct the bishop's diagonal, while a bishop capture can obstruct the rook's line. The composer exploits the two captures as different variations.

The Novotny is closely related to the Grimshaw. Both rely on reciprocal interference between two defensive lines. The essential difference is that a Novotny begins with the opposing side placing a sacrificial piece on the intersection to trigger that interference.