Large deep purple flowers with a red bar. Silvery-purple or red anthers. According to Toomey & Leeds and the International Clematis Register and Checklist, 'Akaishi' is the name of a Japanese mountain; Robin Savill contends that it means 'Red Stone' and is the name of a Japanese town.

Maurice Horn has a further clarification of the origin of the name, from talking to Japanese growers he met in the mid 1990's. "Akaishi is one of Sakata no Tane Co.'s mountain series. The name refers to Akaishi-dake, a peak which straddles Shizuoka and Nagano Prefectures."

In our experience, this form seems to be somewhat variable. In the first photo the red bar is so wide as to almost overwhelm the purple, in the second the red is more muted and contained, the third image lies somewhere between the two!