Originally Posted by
RichardInSF
Yes, it is most concentrated on the street connecting Okubo station (Chuo-Sobu line, yellow) and Shin Okubo station (Yamanote line, lime green).
That would be Okubo Dori.
Originally Posted by
RichardInSF
At night, it is a well-known area for another type of commerce.
When I first visited Japan (late 80s), it was notorious for being one of the few places in Japan where prostitutes commonly accosted men in the street. These days, there are still a lot of love hotels in the back streets around Hyakunincho etc. but the main street feels pretty "family friendly" to me. It's mostly Korean restaurants and shops selling K-Pop stuff.