As any decent dictionary published after 1980 will tell you, an endorphin is "any of a group of peptide hormones that bind to opiate receptors and are found mainly in the brain. Endorphins reduce the sensation of pain and affect emotions." In other words, they make you feel good.
What triggers this reaction varies slightly from person to person (love, chocolate, etc.). But for Masahiko Ozaki, music is the key -- preferably rock and preferably on 12-inch vinyl. That's why, when he opened his first bar 15 years ago, he called it Endorphin.
The original was in Jiyugaoka -- and Endorphin is still there, though it moved once about five years ago. The only difference between the two is that the stairway to Ozaki's little slice of heaven got shorter as it moved from a second-floor locale to a street-level location. It made no difference. A steady flow of supplicants still made the pilgrimage from all over Tokyo to visit his shrine to '70s rock 'n' roll.