Tenshinkai is the name given by O'Sensei himself to the fluid and powerful style of Aikido out of Vietnam. He personally entrsuted that style to Sensei Dang Thong Phong who currently teaches in Westminster, CA USA. Visit the website, www.Tenshinkai.com
IMHO, the style is a mix of soft and fluid and hard. It is an Aikikai style so the technical proficiency is very important. The motions are relexed and fluid, but the throws and locks are very hard.
Phong Sensei has a 6th dan in Aikikai, a 6th dan in Tae Kwon Do, a 5th dan in Judo, and am 8th dan in Vietnames Shaolin Kung Fu. If you get a look at the demonstrations from the Aiki Expo, Phong Sensei was the first one on Saturday night.