Hiraki is what a Nohgakushi (Noh actor) performs for the first time as a shite (a main actor of a Noh play) or a quasi shite role for a certain music, Kyogen (farce played during a Noh play cycle), or hayashi (musical accompaniment played on traditional Japanese instruments).
披き（ひらき）とは、能楽師が、ある曲のシテもしくはそれに準ずる役、狂言、囃子などをはじめて演ずること。