The nightrider, alternatively spelled knightrider and also known as the knightmare or unicorn (though the latter term sometimes refers to the

bishop A bishop is an ordained clergy member who is entrusted with a position of authority and oversight in a religious institution. In Christianity, bishops are normally responsible for the governance of dioceses. The role or office of bishop is ...

+nightrider compound), is a

fairy chess piece A fairy chess piece, variant chess piece, unorthodox chess piece, or heterodox chess piece is a chess piece not used in conventional chess but incorporated into certain chess variants and some chess problems. Compared to conventional pieces, fair ...

that can move any number of steps as a

knight A knight is a person granted an honorary title of knighthood by a head of state (including the Pope) or representative for service to the monarch, the Christian denomination, church or the country, especially in a military capacity. Knighthood ...

in the same direction. The nightrider is often represented by an altered version of the knight's icon.Piececlopedia: Nightrider
at '' The Chess Variant Pages'' In this article, the nightrider is represented by an inverted knight and notated as ''N''; the knight is abbreviated as ''S'' for the German name ''Springer''. The nightrider was invented by

Thomas Rayner Dawson Thomas Rayner Dawson (28 November 1889 – 16 December 1951) was an English chess problemist and is acknowledged as "the father of Fairy Chess". He invented many fairy pieces and new conditions. He introduced the popular fairy pieces grassh ...

in 1925. It is often used in

chess problems A chess problem, also called a chess composition, is a puzzle set by the composer using chess pieces on a chess board, which presents the solver with a particular task. For instance, a position may be given with the instruction that White is to ...

Movement

The nightrider moves and captures any number of steps as a knight (2 vertically and 1 horizontally or 2 horizontally and 1 vertically) in the same direction. Intervening landing squares must be vacant. For example, a nightrider on b2 can reach the empty square c4 and continue forward to empty squares d6 and e8, but it cannot jump over a pawn on f4 to reach h5.

Value

The nightrider is worth about 5 pawns, similar to the rook. It can control up to 12 squares on an 8×8 board as opposed to the rook's 14. It is stronger than the rook in the opening and middlegame, as it can more easily maneuver around pieces than the rook, but the rook is stronger in the endgame. While king and rook vs. king can force checkmate, king and nightrider vs. king cannot checkmate at all. The nightrider, like the knight, can jump over blockades in closed positions and is good at delivering forks. One benefit of the nightrider's additional mobility is that the nightrider can triangulate while the knight cannot. King, nightrider, and knight vs. king can force checkmate.

Observations

The king together with two knights cannot win the endgame against a lone king (see

Two knights endgame The two knights endgame is a chess endgame with a king and two knights versus a king. In contrast to a king and two bishops (on opposite-colored squares), or a bishop and a knight, a king and two knights cannot checkmate against a lone king (howe ...

), but the king together with a knight and a nightrider can. This is because, unlike the knight, the nightrider can gain a

tempo In musical terminology, tempo ( Italian, 'time'; plural ''tempos'', or ''tempi'' from the Italian plural) is the speed or pace of a given piece. In classical music, tempo is typically indicated with an instruction at the start of a piece (ofte ...

. Solution: 1. Ne7! Ka7 2. Ng3 Ka8 3. Ne4 Ka7 4. Sb5+ Ka8 5. Nd2# With nightriders on the board, a mutual discovered

perpetual check In the game of chess, perpetual check is a situation in which one player can a draw by an unending series of checks. This typically arises when the player who is checking cannot deliver checkmate, and failing to continue the series of checks give ...

is possible. A possible continuation would be: 1. Kd3+ Kc5+ 2. Kc3+ Kd5+ 3. Kd3+ Kc5+, etc. In the diagrammed position, 1...e5 2.fxe6+ (capturing '' en passant'') results in triple check.

References

Bibliography * {{Chess piece Fairy chess pieces 1925 introductions