Again, as for what style you want to achieve is going to determine what lenses you use. I shot street photography for two years straight in Japan using 25mm to 50mm (full frame), and getting close was never an issue as long as you’re quick about it.
The Japanese themselves have produced some of the world’s finest street photographers; and I would recommend that folks check out Daido Moriyama. Moreover, I caught no less than two Japanese guys with cameras chest height taking shots of me (the foreigner/gaijin). Who were they to know that they were photographing a photography geek who was bound to check out every camera in sight.
Whether the subject is going to be comfortable with having people shoot up close is a universal issue, not just a Japanese one, so this should fall on the OP’s judgment. You don’t have to shove a camera two feet in front of the subject’s face to be close.
Also, for one, I never photograph children, the homeless, people sleeping, or anyone doing something that might be embarrassing (Golden Rule, would I want to be photographed doing this?). These are personal restrictions, but if you respect what you are doing and are quick and discrete, most people don’t mind let alone even notice. I even got a rare shot of Yakuza late at night in Kabuki-chou and survived.