Which model do you have? Shuns are kinda like hydrids and take some elements from German knives and some from Japanese. KAI, the parent company of Shun, recommends users target a 16* angle when sharpening.
Classic 8" Kiritsuke
'... this is by far the sharpest knife I've ever used and the design of the blade makes for such comfortable and precise cutting.' Fine Japanese cutlery, handcrafted in Japan.
shun.kaiusa.com
Their page agrees with 16 degrees. But I don't know what that means without context...