Tieguanyin, formally should be spelled as Tie’guanyin, aka Te Guan Yin, or Teguanyin, Iron Goddess of Mercy, Tit Koon Yum, Guanyin etc is the most known oolong from the Minnan area. There are two popular finishes — bouquet and browned. For the bouquet style, there are two popular harvests: Spring and Autumn.