The Japanese 4th single "Yoi -YOI-" is a work that expresses "desire and instinct" toward a loved one through three tracks. Limited Edition B comes with a 36-page photobook and a book cover B (EN ver.), a 6-page lyric book, a selfie photo card B (EN ver.) (randomly selected from seven kinds), and a photo card B (EN ver.) (randomly selected from seven kinds).