"Hokumen no bushi" were samurai who served the retired emperor, standing by as the gero (servant) on the north side of the in (imperial palace of the retired emperor), and guarding or accompanying the retired emperor when he made trips outside..
北面武士(ほくめんのぶし)とは、太上天皇に仕え、院の北面下臈に詰め、身辺の警衛あるいは御幸に供奉した武士のこと。