"Kuroge Wagyu Joshio Tanyaki 680-en" (黒毛和牛上塩タン焼680円, Kuroge Wagyū Jōshio Tanyaki Roppyaku Hachijū-en) is Ai Otsuka's seventh single. It was released on 9 February 2005, by Avex Trax. The title is roughly translated as "680 yen salty grilled black Japanese beef tongue." The song was used as ending theme for TV Tokyo's 2005 anime series Black Jack. This single sold 149,134 copies and it became the #68 best selling single of 2005. The b-sides included on the maxi single are all related to meat types with its respective prices.