The discovery of two new magic knight’s tours

Abstract

A magic square is one in which all rows and columns, and the two main diagonals, sum to the same total. A knight’s tour is a tour of the board in which, using knight’s moves, all squares are visited exactly once. When the squares visited are numbered from 1 to 64, if the square is magic (but without including the two main diagonals), this is termed a magic knight’s tour. This paper describes two magic knight’s tours on an 8 by 8 board found in early 2003, the first new tours to be discovered since 1988, and the first irregular tours to be discovered since 1936.