I wouldn't have thought so, not for nothing.

For instance, at Shinagawa there are lots of shops and facilities, as well as Shinkansen train platforms, that people want to access without actually going anywhere.

The solution is to buy a platform ticket, and I think that's the same as a minimum ride - around 130yen. I understand it's good for 2 hours.

Obviously if you really wanted to you could go right round the Yamanote line and disembark at the same or nearby station for the minimum fare. You might need to explain why so much time had elapsed since you validated the ticket at the entrance barrier, nevertheless you can complete the route in under 2 hours so you'd technically be allowed... but why would you want to???

There is an established hike that some people do, it's called the Yamanote Line Challenge and involves walking around Tokyo following the tracks and picking up discarded ticket stubs at every station to 'prove' your attempt is genuine. It usually takes a reasonably fit person between 12 and 14 hours although you'd be nuts to do this in the summer.

There's a lovely blog describing the experience here: http://smt.blogs.com/tokyo_travel/20...challenge.html

Other people do the route on bicycle: http://smt.blogs.com/tokyo_travel/20...challenge.html