There is an image of this cultivar on the Hosta Library. From the photo on the HL website, it appears to be a small size hosta with green leaves and creamy yellow streaked variegation. There seems to be some red dots on the petioles. It bears pale lavender flowers. This non-registered cultivar was originated in Japan and was introduced by Kosasa of Japan.

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 and the term nishiki as brocade (rich-colored woven fabric) i.e. something colorful and beautiful.