吐夢 (Pronounced "To-mu" or just "Tom") is unique in a couple of ways. Its got two rooms with large tables in both along with one long counter; they cook up a lot of fairly good food (rare to get tasty grub in jazz joints); there are about a hundred signed baseballs up on the top shelf above the bar, right over about 3000+ albums; it has a very spacious vibe that you don't get at most jazz bars in the center of Tokyo.
吐夢 has been in Asagaya for more than forty years and is well known by most locals. The music almost always fits the mood; when it's quiet and fairly empty you get some slow burning blues or hard-bop. When it's packed and noisy you get some hard-swinging soul-jazz or even big band. It's a good place for larger groups who want to drink a bit but still get to hear some swinging tunes. One of my favorite of many great jazz bars along the JR Chuo railway line.
Extra star for having a special 400 yen happy hour for glasses of Ebisu draft beer. Bargain for a jazz bar. See more pics of Tom over at Tokyo Jazz Joints.
Station: JR Asagaya
Exit: South Exit
Distance from station: 3 minutes
Turn right out of the South Exit, walk along the tracks right past the Smile Hotel. Look to your left after the Smile Hotel, you'll see the sign.