The screw pump is a screw inside a hollow pipe. At the bottom end of the pipe the screw scoops up water and transfers the water up the pipe.

In this week’s position white threatens an immediate mate with its queen-bishop battery. Black, however, scoops out white’s pieces near its king and then puts the screws to white’s mating attack by forcing a draw by repetition. With this in mind please try to find how black draws.

White’s queen-bishop battery immediately mates on h8, or g7 if black’s bishop moves somewhere else along the f8-a3 diagonal. Because of this, black must check white or lose. First, black scoops away white’s pieces with a series of checks, beginning with moving the rook at b3 to b1. White must recapture black’s b1rook with its c1 rook. Black’s pawn at a2 captures white’s rook at b1, checking white as the pawn promotes to a queen.

White’s king is forced to take black’s new queen. Black’s other queen now checks white from f1. If white’s king moves to b2, black mates with its rook and queen by sliding its queen to a1. Thus, white must block the queen check by moving its rook to c1.

Now what? The Greek inventor Archimedes, who created the screw pump and is on history’s short list for world’s greatest scientists, solved innumerable puzzles. He immortalized the word “Eureka” when he was in his bathtub and thought of applying the principle of buoyancy to determine the density of objects. This allowed him to see if the King’s crown was indeed made of gold.

Here, the eureka moment, as it were, is seeing that checking white with the black rook from a1 saves black and leads to a draw. If the king moves to b2 instead of taking the rook, the black queen grabs the white rook with check and white is soon mated. White’s king thus takes the black rook. Black’s queen then takes white’s rook with check.

From here, the black queen continues to check the white king perpetually along the “c” file, as the white king moves up and down along the “a” file. The white king cannot move past the a3 square, or the black queen and bishop mate black on a4.

The lesson here is that when all seems lost, let your imagination scoop up the pieces and search for a hidden eureka moment. It just may put the screws to your opponent’s plans.