Changed his main english name from Richard Yung Ga-Chai to Richard Yung Ka-Tsai as he mentions on his own MySpace page - http://www.myspace.com/yungkatsai
He was a part of duo "TsaiShing" - the name was a combination of his name (Ka-Tsai) and the other member's Joseph Chow Kung-Shing.
So it should be "Ka-Tsai"