SAT: A king is in check if any of its flight squares are unguarded by opposing pieces.
Grasshopper(G): Moves along Q-lines over another unit of either color to the square immediately beyond that unit. A capture may be made on arrival, but the hurdle is not affected.
Royal piece: Piece that executes a function of the King on the board.
Here we feature the Dalton theme (an unpinned piece moves and pins its unpinner), combined with focal play.
In the diagram both the black knights are pinned.
In the defences the rook moves to give White an escape square, first on h7 then on e2.
However in doing so it gives up its guard of a8 and h7.
This leads to the Dalton sequences leaving the white knight pinned to those squares. (Author)
