Nightrider (chess)

abcdefgh
8
e8 black cross
d6 black cross
a4 black cross
c4 black cross
f4 white pawn
d3 black cross
b2 N l
d1 black cross
8
77
66
55
44
33
22
11
abcdefgh
Nightrider makes any number of knight moves in the same direction.

A nightrider (also known as a knightmare or unicorn, though the latter sometimes also means the bishop–nightrider compound) 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 the f4-pawn 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.


Examples

T. R. Dawson, British Chess Magazine (1925)
abcdefgh
8
c7 white king
a6 black king
c6 N l
c3 white knight
8
77
66
55
44
33
22
11
abcdefgh
#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#

abcdefgh
8
c6 black rook
d6 black rook
d5 black king
c3 white king
b1 N l
e1 N l
8
77
66
55
44
33
22
11
abcdefgh
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.

abcdefgh
8
e7 black pawn
f7 black king
f5 white pawn
d3 N l
f1 white rook
g1 white king
8
77
66
55
44
33
22
11
abcdefgh
After Black moves his pawn to e5, taking it en passant results in triple check.

Nightrider can also participate in triple check.

References

External links

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