Book  (Oct 2001)  Page(s) 103-104.  Includes photo(s).
 
Clematis 'Akaishi'
Raised in Japan by Sakata no Tane Company and named after a mountain
Parentage and year: unknown
... single, deep purple flowers... eight boat-shaped, pointed tepals, each with wavy margins and a prominent cerise-pink central bar. Stamens are made of pinkish filaments tipped with silvery purple anthers...