01.09.10 The chess problem, or chess composition, is a puzzle in which the solver is asked to find or complete a specific task. Unlike tactical exercises, the chess problem does not necessarily seek to find the objectively strongest move in a given position. There are many genres of chess problems; in this post, we will consider a particular type of chess problem know as the proof game. In proof game problems, the solver is given a move or position and is asked to construct a game that ends in that position.

In addition to the technical correctness of a particular problem, composing and solving chess problems involves the consideration of beauty and aesthetics. While there are no hard-and-fast rules for judging the aesthetic content of a problem, there are, however, as in the field of art appreciation, important elements that the problem should involve including: economy, legality, illustration of a theme, non-obviousness, and so on.

Today's proof game problem, composed by an American International Master, had one of the premier chess composition solvers, Dr. John Nunn, scratching his head until he realized there were more than one sequence of moves that would lead to the desired position.

Are you ready?

Here it is:

(Not 6...Nxf1 mate, but 6...Nf1 mate.)

Good luck!