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 yellow leaves and
white streaked variegation. It is a sport of H.
Leafy bracts appear along the stem and near white
flowers are borne in August. The flowers have dark purple veins
in the tepals. This non-registered cultivar was originated by
Alex Malloy of New York.
Mikiko Lockwood in an article on The Hosta Library titled,
A Little About Japanese Hosta Terms defines the term koba as small leaf,
'Koba Giboshi' or
H. sieboldii and the term ogon or oogon as gold or yellow.