It seems like it's missing most of Tokyo?
Granted, Tokyo has a blended commuter / subway through-service system (eg, Fukutoshin-line trains continue into the Toyoko-line), but those trains don't seem to show up in either Rail or Subway views.
Granted, Tokyo has a blended commuter / subway through-service system (eg, Fukutoshin-line trains continue into the Toyoko-line), but those trains don't seem to show up in either Rail or Subway views.
Most likely, they just left out the JR Rail and other lines because the map is way too complicated with them, or perhaps it broke their algorithm.
They also didn't show the entire Tokyo metro area, which is much larger than this and includes Yokohama. It's understandable, though: the entire Tokyo metro area is enormous (though perhaps not compared to many American cities like Phoenix, if you just look at land area, but those cities have nowhere near the density of Tokyo), and a map of the entire thing is usually too complicated to bother with, so zoomed-in maps are more useful. This one is showing central Tokyo (the part encircled by the Yamanote line) and parts not too far from it.
The answer for this, I think, is that either the OSM data (input) needs to adapt to fit what this system can read or patch rules and patch data can be applied to fix up the output.
Either way it is a distributed project, people in Tokyo or Hannover or any place where it is wrong are the people who would know what is right so they should be engaged in the solution.
It shows the subways, but also adds on the relevant JR rail lines and lines from other companies. Honestly, I don't see how this project could improve on this; the current map is already packed full of information.