In shogi, Fourth File Rook (四間飛車 shikenbisha) is a class of Ranging Rook openings in which the rook is initially positioned on the fourth file if played by White or the sixth file if played by Black.
Fourth File Rook against Black's King's Head Vanguard Pawn (玉頭位取り gyokutou kuraidori).
The Leghorn Special (白色レグホン・スペシャル hakushoku reguhon supesharu or, most commonly, the abbreviation レグスペ regusupe) is an opening in which you build up a Bear-in-the-hole castle while you're simultaneously defending against an opponent's Bear-in-the-hole.
The name is said to have originated in the resemblance of this opening to the behavior of a white leghorn chicken that keeps attacking when surrounded by Bear-in-the-hole.
[citation needed] The leghorn special consists mainly in castling the king in Bear-in-the-hole once the bishops have been exchanged in Fourth File Rook.