This is a "form" of
Japan which forms a small size clump of green
foliage with a yellow marginal variegation. It bears
purple flowers in August.
The Hostapedia by Mark Zilis (2009), "...formerly listed as H. sieboldii f. kifukurin..."
Mikiko Lockwood in an article on The Hosta Library titled,
A Little About Japanese Hosta Terms defines the term kifukurin or ki fukurin as yellow edge(d) or
yellow margin(ed) and the term koba as small leaf, 'Koba Giboshi' or