B'z The Best "Treasure" is the fourth compilation album by the Japanese rock duo B'z. It fincludes many of their hit singles from 1990 to that date: all 14 songs are #1 hits. The songs on this album were selected by a poll of B'z fans. The album reached 1st at Oricon with over 2.5 million copies sold in its first week. It has sold more than 4.4 million copies to date, making it the fifth best-selling album in Japanese music history.