Yuu Aku was a renowned Japanese lyricist who contributed significantly to the music industry from 1967 to 2007. During his career, he wrote lyrics for over 500 singles that entered the record chart and sold more than 68 million copies. His compositions were particularly successful in the 1970s, with many reaching #1 on the Japanese Oricon chart and selling more than a million copies each. Aku's contributions made him one of the most commercially successful lyricists in Japan up to that point, surpassed only by Yasushi Akimoto. He won five Japan Record Awards throughout his career and was also recognized as a novelist, producing several award-winning works. In 1999, Aku received the Purple Ribboned Medal of Honor from the Government of Japan for his long-term contributions to the Japanese entertainment industry. Despite being diagnosed with kidney cancer in 2001 and undergoing chemotherapy until his death in 2007 due to ureteral cancer, Aku continued working until the very end.