There are also a number of tiny cubby sized jazz-themed bars in Shinjuku's Golden Gai district, like Jazz Bar Baltimore, that might be worth exploring. The biggest appeal of these places is that due to their size (and the $8-10 door cover and expensive pours) you'll end up spending a good part of your evening mixing with other enthusiasts and aficionados, so it can be a lot of fun if you're able to communicate with the bartender and other patrons. Your best bet is to just wander through the narrow maze-like alleyways until you find the 'right' atmosphere. Don't bother showing up before 9:30-10pm though, as most shops won't be open yet.