💡📝Jörg Knappen wrote on Thu, Oct 22, 2009 06:25 AM EDT:
Can mate property: The following two crooked nightriders can mate a single king with the help of their own king: Straight, Wide Crooked Nightrider (Enger Spiralspringer) and Diagonal Wide Crooked Nightrider (Enger Diagonalspiralspringer).
I don't succeed in mating with the quintessence, but I am not sure if mating is really impossible, since it can get close to a checkmate. An endgame analysis with the help of the computer can provide a definitive answer here.