When were you last there in Japantown, Bev? For the past 6 years I have been going there, Katsura has always been on the ground floor of that building, have never seen it on the 2nd floor. The only difference I saw in that building was the expansion of the bookstore to the ground level where the garden shop is as well as the other newer shops. Anyways, hope you can locate it when you try visiting the place once more.
I always like to visit that garden shop, it is a small store but it has really nice assortment of shallow clay containers good for succulents, which is used in bonsai, and the people managing it is very nice as well. I like watching how they do their bonsai, and they are nice enough to let me watch while they mix their soil or repot some.