I thank Christoph Bandelow for allowing this chess problem, with a mathematical flavor, to be posted here.

Position:

• In algebraic:White: King c7, Rooks c3 and d3, Knights b1 and e1,
  Pawn e3 (6 pieces).Black: King b5, Knight a4 and c4, Knights
  a4 and c4, Pawns a7, b6, and a5 (7 pieces).
• In Forsyth notation:

  8
  p1K5
  rp6
  pk6
  n1n5
  2RRP3
  8
  1N2N3
  

From the chess problem collection “Problem-Juwelen” by Herbert Grasemann. Publisher: Siegfried Engelhardt Verlag, Berlin 1964.

White to mate in 6 (Christoph Bandelow, 1959)

Solution: 1. Rb3+ … 2. Rb5+ … 3. Rb3+ … 4. Rb5+ … 5. Nd3

This problem was originally posted at http://www.permutationpuzzles.org/chess/bandelow3.html.