A nightrider (also known as a knightmare or unicorn) is a fairy chess piece that can move any number of steps as a knight in the same direction. Intervening squares must be vacant. For example, a nightrider on b2 can reach square c4 and forward to d6 and e8, but cannot jump over pawn f4 to reach h5. The nightrider is usually represented by an inverted knight in diagrams, and symbol N in text (in which case the knight is abbreviated as S for German Springer).
|This article uses algebraic notation to describe chess moves.|
The king together with two knights cannot win endgame against a lone king (KSS vs K), but the king together with a knight and a nightrider can win, because the knight cannot win a tempo, but the nightrider can.
Solution: 1. Ne7! Ka7 2. Ng3 Ka8 3. Ne4 Ka7 4. Sb5+ Ka8 5. Nd2#
A possible continuation would be: 1. Kd3+ Kc5+ 2. Kc3+ Kd5+ 3. Kd3+ Kc5+, etc.
Nightrider can also participate in triple check.
- Hooper, David; Whyld, Kenneth (1992), The Oxford Companion to Chess (2nd ed.), Oxford University Press, ISBN 0-19-280049-3