This is a sport of the species,
H. kikutii polyneuron and is a non-registered variety
from Shikoku Island in
Japan. It forms
a medium size mound of
streaked foliage with leaves that are narrowly elliptic.
Lavender flowers bloom from August into September.
Mikiko Lockwood in an article on The Hosta Library titled,
A Little About Japanese Hosta Terms defines the term
-gawa or -kawa as river.