This cultivar was listed on the
MyHostas Database website.
Originated in Japan, this non-registered cultivar is a sport
of H. kikutii var. polyneuron. It is
a medium size hosta with narrow green foliage that has a
white medial (center) variegation. 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 shironakafu or shiro nakafu as white-center(ed).