I was sorry to read in the latest issue of The Problemist that one of our leading problem composers, Colin Sydenham (1937-2023), died last November.

One of Colin’s specialities was the Duplex Helpmate. In a normal helpmate in 2, Black plays first and both players work together to produce a position where White’s second move delivers checkmate. In a Duplex Helpmate in 2, when you’ve done that you have to do it again from the same position, but this time with White playing first and Black’s second move being mate.

Here’s a simple example (1HM Schach-Echo 1989-90). I’m sure you can find both solutions.