This non-registered cultivar was originated by Shinya Fukatsu of Japan. According to an article by the originator in The British Hosta and Hemerocallis Society Journal (Autumn 2019) this is a medium to large size hosta which is the all-green sport of H. 'Shisen'. It is a very upright growing plant with reddish-purple petioles which is covered with a white bloom as are the top and bottom of the leaves. The light lavender flowers stand on purplish colored scapes well above the foliage.
 

Mikiko Lockwood in an article on The Hosta Library titled, A Little About Japanese Hosta Terms defines the term iwa as rock, Iwa Gibōshi or H. longipes.