Tatsurō Yamashita (山下 達郎, Yamashita Tatsurō, born February 4, 1953), occasionally credited as Tatsu Yamashita or Tats Yamashita, is a Japanese singer-songwriter and record producer often referred to as the "King of City Pop" for pioneering that style of Japanese adult-oriented rock/soft rock music. His most well-known song is "Christmas Eve", the best-selling single song released in Japan in the 1980s, appearing on the Japanese singles chart for over 35 consecutive years. He is known for his collaborations with his wife and popular singer Mariya Takeuchi on many songs including "Plastic Love" as well as with American songwriter Alan O'Day with whom he wrote hit songs "Your Eyes", "Magic Ways" "Love Can Go the Distance" and "Fragile". Active since the 1970s, Yamashita is considered an important contributor to Japanese music, ranked by HMV Japan as sixth in the Top 100 Japanese Artists.