Who can resist a restaurant called "Mom's", especially when the kitchen and waitress staff is a squadron of fifty-ish, motherly types who look like they'd be disappointed in you for not finishing your vegetables. But the main draw here is the sake -- they promise a "journey through Japan by sake", and they stock close to 100 brands, from every part of the country, with most varieties running Y500-Y800 per glass. There's also a respectable menu of izakaya-style food, with grilled chicken wings, duck steak, and plenty of seasonal items. No English.
Nishi-Shinjuku 1-11-11, B1F. (on the side street directly behind Yodobashi Camera honten) Open 11am-3, 4-11:20pm (LO). Closed Sundays.