Ishida Bungu is a stationary store based in Hakodate, Hokkaido (Northern Japan).  I came to learn of their inks only very recently via discussions of Hakodate Twighlight ad Gagome on the pen forums.  You can buy Ishida Bunga inks at the White Rabbit Express service.  They do not ship outside of Japan.

In pursuit of my bottle of Pen & Message Cigar in the Winter/Spring of 2017, I decided to get the other 6 colours in the P&M set, as well as 4 inks from Ishida Bungu stationary store, namely; Hakodate Twighlight, Curry, Gagome (Brown Algae) and Old School Brown.  My thinking being if I spread the cost of shipping over more bottles of ink I’ll actually be saving money(!).