Nazo (song)
Chart performance. The single reached number 9 in its first week and sold 40,230 copies. The single charted for 32 weeks and sold 325,850 copies overall. This was her highest sold single in her career up until then. In media. "Nazo" was used in anime "Case Closed (Detective Conan)" as third opening theme, although the single version differs from the on-air version. "Kotoba ni Dekinai" was used as ending theme for Nagoya TV program "Yoshimoto Gozensama Party". Track listing. Covers. The song was first covered in 2004 by Korean girl-group Jewerly in their single "Superstar" as  coupling song in Korean language. In 2008, Aiuchi Rina and U-ka Saegusa in dB cover this song in their single "100 Mono no Tobira"". La Pompon. In 2015, the Japanese pop girl group La PomPon covered the song as the 41st opening theme song of "Detective Conan".