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.