Itachibori 3-5-1. [1 blk E of Itachibori 3-minami crossing] Open 9am-7pm (6pm Sat). Closed Sundays.
Beneath this ordinary-looking sake shop - through a hole in the floor and down a narrow ladder - is a hidden sake tasting cave with a big selection of premium sake from around the country, including many koshu (aged sakes). Tasting-size glasses are just Y200 each, and the only food is chunky miso from Wakayama and umeboshi (also Y200 each).