Cao Youyin (曹又尹), formerly known as Cao Cheng (曹呈), is a Chinese pro 3 dan born 1987-02-16. She was promoted 1 dan in 2000, 2 dan in 2005 and 3 dan on 2009-07-30.
2001: Runner up in the short-lived Tombow Cup
2007: Winner of the 1st Female Xinren Wang
2007: Quarterfinalist in the single-edition Dali Cup
2008: Quarterfinalist (?) in the single-edition Yuanyang Cup
2010: Winner of the Chinese National Women Individual
2011-09-25: Winner (2nd time) of the Chinese National Women Individual
2011: Runner up in the 9th Jianqiao Cup
2012: Placed fourth in the short-lived China Female Guoshou
2013: Winner (3rd time) of the Chinese National Women Individual
2014: Winner of the 12th Jianqiao Cup
She was a member of the Chinese team for the 2014 Huang Longshi Shuang Deng Cup, and for both the 2005 and 2009-10 editions of the Cheongkwanjang Cup.