Nightrider (chess)

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a b c d e f g h
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e8 black cross
d6 black cross
a4 black cross
c4 black cross
f4 white pawn
d3 black cross
b2 white upside-down knight
d1 black cross
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Nightrider makes any number of knight moves in the same direction.

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).

The nightrider was invented by T. R. Dawson in 1925, and is mostly used in chess problems.

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Examples[edit]

T. R. Dawson, British Chess Magazine (1925)
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c7 white king
a6 black king
c6 white upside-down knight
c3 white knight
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#5 (Nightrider c6)


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 b c d e f g h
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c6 black rook
d6 black rook
d5 black king
c3 white king
b1 white upside-down knight
e1 white upside-down knight
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Mutual discovered perpetual check with nightriders

With nightriders on the board, a mutual discovered perpetual check is possible.

A possible continuation would be: 1. Kd3+ Kc5+ 2. Kc3+ Kd5+ 3. Kd3+ Kc5+, etc.

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e7 black pawn
f7 black king
f5 white pawn
d3 white upside-down knight
f1 white rook
g1 white king
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After Black moves his pawn to e5, taking it en passant results in triple check.

Nightrider can also participate in triple check.

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