First File Rook

In shogi, First File Rook (一間飛車 "ikkenbisha" or "ichigenbisha") is a Static Rook surprise opening in which the player's rook supports an attack on the player's rightmost edge file.
The player may also attempt to move the lance first and set the rook behind it to attack via the first file, but this is rarely to no used in professional play, since white can counterattack by pushing their rook pawn.