Spend a night listening to jazz in Kannai and Isezaki-cho
As Yokohama has been the gateway for international culture, jazz music was introduced to this area many years ago. There are many old, yet still active jazz bars there. If you check the bar websites, you might find that your favorite internationally recognized players are performing in this area! Most of the bars are small, so you might even get a chance to talk to the players when they are taking a break.
(Source: Japan Travel by NAVITIME)