By Awani Kumar, Lucknow, India
The Royal Dutch Chess Federation (Koninklijke Nederlandse Schaakbond - KNSB) -- the national organization for chess -- was founded on May 23, 1873 and is one of the country's oldest sports federations. The author wishes to celebrate and commemorate its 150th anniversary with some interesting knight tours on 10x15 (= 150) board. Figure 1 is semi-magic knight tour. Here sum of all the columns is 755. Since it is a tour on ‘even by odd’ size board, so there are unequal number of light and dark squares along the rows. Therefore, the rows will be alternately even and odd and thus can’t have a magic sum.
Fig.1. Semi-magic knight tour on 10x15 board
Figured tour of knight is a piece of mathematical art. Figure 2 to Figure 5 are monogram tours (knight moves delineating letters) with square numbers 12, 22, 32, …, 122, namely, 1, 4, 9, …, 144 delineating ‘K’, ‘N’, ‘S’ and ‘B’, the first letters of Koninklijke Nederlandse Schaakbond. Figure 6 to Figure 8 delineate ‘1’, ‘5’, and ‘0’; the numerals in 150.
Congratulations KNSB for successfully completing 150 years and we wish to celebrate its bicentenary. Amen.