ABSTRACT
Knight Interchanges can provide a pleasant diversion. The classic problem attributed to Henry E. Dudeney is the interchange of knights, whereby the positions of the black and white knights are to be interchanged using the usual knight moves and not allowing more than one knight on a square at a time. Dudeney reasoned that the problem could be formulated in graphical terms. A 4 × 4 board becomes more complicated as far as knight interchanges are concerned. Attempting the solution by trial and error is laborious and can often lead to the assumption that no solution is possible. The permissible moves are redrawn to reveal the planar graph with 3 circuits.
