Ketzai booklets, which are also known as Fukienese or Taiwanese song booklets, contain lyrics set to the tunes of popular songs from ketzai theater (Fukienese or Taiwanese opera). Following the form of seven characters to a line and four rhymed lines to a stanza, the ketzai singers would improvise on the theme of an old folk tale or a major social event.
歌仔冊，也叫歌仔簿、閩台歌冊，通常以發源於台灣且最受歡迎的歌仔戲為曲調，由歌者即興填詞，七字一句、四句一聯，順口押韻，唱出民間故事、社會大事。