The most popular cake in Japan is probably ショートケーキ (shortcake), which is a type of layer cake. Usually a strawberry on top and in one of the layer with cream.
A good site to check how certain cakes look like or call at pâtisserie is here:
(my goto when I live in Ebisu)
Mont Blanc aux marrons
A good one in Kyoto: http://www.malebranche.co.jp/montblanc/
Any place sells cake.
A place sells cake and bakery. Originated from France and Belgium. The chef need to pass sort of certifications.