Since returning, people have asked me "How was Tokyo?" and my answers may include words such as amazing, crazy, taxing, beautiful. There's no doubt though, one word will always crop up: Massive!
It's hard to convey to people quite how big this city is. I mean, Wikipedia lists it as the 8th most populous city, and that's great, but I'm not trying to explain how many people live here - Shanghai is without competition on that front. Sure, it's densely populated, but I never felt cramped. But as urban areas go, it wins out every time.
The Keihin region is the actual urban area, and as a traveller that is what matters. I don't give two hoots about where a boundary is, I am talking about how far I need to travel to leave the city. Keihin contains Tokyo, Kawasaki and Yokohama - but the reality is that they merge into each other. A good example is riding the Shinkansen into Tokyo - from Yokohama to Tokyo you are for all intents and purposes in one city. Sure there are a few beautiful parks dotted along the route, but that's the only greenery that you'll see. Yet still, that conveys nothing to someone who hasn't been. So I found this amazing overlay of Tokyo (proper - just Tokyo, not the whole Keihin region), and I think it gives an idea of scale...