opening act; introductory part
Refers to the first segment of a performance, narrative, or event, often used in contexts like theater, concerts, or serialized stories.
The opening act of the concert was performed by a new band.
The introductory part of this novel depicts the protagonist's childhood.
オープニング is a common loanword for 'opening', used in events, ceremonies, or media, but 開幕編 specifically implies a structured part or act.
Compound of 開幕 (かいまく, 'raising the curtain; opening') and 編 (へん, 'chapter; part; volume'). The term likely emerged in modern Japanese to describe the opening segment of performances or serialized works.