Jazz Olympus was opened by the very friendly Komatsu-san in 2009. It's a sleek cafe/bar that is already well known in the area for it's lunch-time menu (rare is the jazz cafe with good food!). Komatsu-san has a nice collection of about 4000 records and CDs in the place, with some beautiful album covers hanging on a few of the walls. His collection is mainly from the 50s and 60s but not exclusively, and he'll play any genre of jazz depending on the time of day. When I was there on a sleepy, rainy Monday afternoon it was Anita O'Day coming out of the exquisite sounding speakers.
Komatsu-san also has record sharing and record release events at the cafe about once a month. There are flyers by the front door but don't be afraid to ask him about them if you can't read Japanese. Olympus is another great spot on the now plentiful Ochanomizu jazz joint map. Non-smoking until 2pm.
Station: JR Ochanomizu Station, Toei Shinjuku Line Ogawamachi Station
Exit: JR Ochanomizu-bashi Exit, Ogawamachi Station Exit A6
Distance from station: 5 minutes