This is one of those cases where there are two hostas with the same name. One is registered and, therefore, the "official" version of H. 'Blue Star' while the other is a non-registered plant and needs to be renamed to avoid further confusion.

This medium size (14 inches high by 30 inches wide), blue-green cultivar was registered by Jody Brennan of Pennsylvania in 1998. It is noted for its intensely blue-green foliage which has thick substance and is slightly rippled. Pale lavender, tubular flowers bloom in July.

Hosta Helper will call this plant 'Blue Star' (Brennan)

There is also a non-registered cultivar by this name from Dr. Ralph (Herb) Benedict of Michigan. Of course, the registered plant takes precedence for the name, 'Blue Star'.

Hosta Helper will call this plant 'Blue Star' (Benedict)

From the Field Guide to Hostas by Mark Zilis (2014), "...'Blue Star' was offered for sale by Gotemba Nursery...Japan for many years...Peter Ruh of Ohio registered (in 2001) Kenji Watanabe's plant as 'Evening Star'...I suspect that the name 'Blue Star' will still be used in Japan for a while."

Hosta Helper will call this plant 'Blue Star' (Watanabe)