Locust (fairy chess piece)
Locust
Definition
The Locust is a fairy-chess piece (i.e., a unit used in chess problems or variants, not in orthodox over-the-board play). It belongs to the family of hoppers: pieces that move by leaping over another unit. A Locust makes a single hop over any adjacent piece of either color and lands on the first empty square immediately beyond. The distinctive feature is that the piece being hopped over is captured; the arrival square itself must be vacant.
Movement & Capture
- Direction: Usually the Locust can move along queen lines (orthogonal and diagonal) unless the composer specifies rook-locust or bishop-locust subtypes.
- Pre-condition: There must be an occupied square directly next to the Locust in the chosen direction.
- Hop: The Locust leaps over that adjacent unit to the next square on the same line.
- Capture: The hopped-over unit is removed from the board; the landing square must be empty, or the move is illegal.
- Analogy: Think of a draughts (checkers) jump, but limited to one square beyond the victim.
Notation
Problemists normally write L for a white Locust and l for a black Locust. In fairy PGN you might see a move such as 1. Lxb3-a4, meaning “White Locust captures on b3 by hopping to a4.”
Typical Usage in Chess Composition
Because its capture mechanism relies on a victim piece, the Locust is a favorite in tasks where the composer wishes to:
- Create dramatic switchbacks: a Locust hops one way, another Locust later hops back over the first victim.
- Engineer precise line-clearances or battery plays that would be impossible with ordinary pieces.
- Explore reciprocal captures—for example, a white Locust captures a black Locust and vice-versa in mirrored fashion.
Strategic & Thematic Significance
Strategically, the Locust forces composers to consider intermediate occupancy; without a neighboring unit, the Locust is powerless. This promotes themes of:
- Tempo management—timing when a square becomes occupied so the Locust can spring into action.
- Dual avoidance—preventing cooks (unintended solutions) by exploiting the Locust’s dependence on a hurdle.
- Mutual obstruction—using friendly pieces as temporary hurdles that will themselves disappear after the hop.
Historical Notes
The Locust was introduced by the German problemist Fritz Giegold in 1953, inspired by earlier “grasshopper” experiments of Johannes Kohtz and Carl Kockelkorn. Its name evokes the biblical plague: the piece devours the very unit that enables its journey.
Illustrative Example
Consider the following help-mate in 2 (h#2) published by Giegold (1954). White pieces: King g1, Locust a3. Black pieces: King g8, Rook b3, Locust b2. Goal: Black moves first, both sides cooperate so that White mates Black king on move 2.
Solution:
- 1... lxb3-b4 2. Lxb4-b5#
First the black Locust on b2 hops over its own rook on b3, capturing it and landing on b4. This provides the necessary hurdle for White’s Locust on a3, which then hops over the new occupant b4, landing on b5 and delivering mate—b5 is now guarded by the white Locust, and every flight square of the black king is controlled or blocked.
Variations & Relatives
- Rook-Locust: Hops only orthogonally.
- Bishop-Locust: Hops only diagonally.
- Grasshopper: Similar hopper that does not capture the hurdle; captures only on the landing square.
- Spider, Flea: Other whimsical hopper pieces exploring different hop lengths or multiple victims.
Trivia & Anecdotes
- Locusts often appear in serial compositions, where one side makes many consecutive moves; their dependence on an adjacent victim creates intriguing long sequences.
- Some problem tourneys award a special prize for the best “Locust field,” a term for a matrix of interlocking locust hops.
- Despite its ferocious name, the Locust is helpless on an otherwise empty board—give it a single pawn to chew on, and chaos ensues!
Further Study
If you enjoy the Locust, explore problems featuring mixed batteries of L + G (Locust & Grasshopper) or combinations with Anti-Kings to see how composers blend multiple fairy conditions.