Doric is from the previous ‘era’ when Kuma was mixing styles, calling that postmodernism. This article is telling very well his aim and the history of his early works.
Nowadays they seems utterly awkward indeed. He was not working that much with the materials yet. According to the interview in the 24 architects book, he switched his career after contacting a wood master, from whom he learned how to deal with the wood.
There is also a video on youtube that lasts 1’33 dedicated entirely to this building.
The good thing is that the street, Aoyama dori, is plenty of nice architecture. You will be amused by a walk there.
HEre the exact location.