There are two places in Tokyo named after valleys favored by the melodious uguisu (Japanese bush warbler): Uguisudani Station on the Yamanote Line, and Uguisudanicho, a small neighborhood wedged between Daikanyama, Ebisu and Shibuya. On a day of early winter blue skies, I wing off to explore the latter.

I land briefly at Yamadaya Manju Gen, a purveyor of delicate bean-paste treats originating from Ehime Prefecture. Shop manager Masahiro Norimatsu, 39, tells me that Yamadaya Manju¡¯s diminutive buns have kept the company in business since 1867.

¡°The ingredients are quite simple, just sugar, beans and wheat,¡± Norimatsu says, ¡°But we use a large-crystal sugar, a melt-in-your-mouth smooth koshian bean paste and a covering that is exceptionally thin.¡±