We noted recently that the mapping data available to Windows Phone users in Japan was pretty atrocious, mostly not including even major roads.
It seems with the latest Windows 10 Mobile Technical Preview this has changed dramatically, with a Japanese user on Reddit noting:
The game is back on for us folks located here in Japan. Happy to say that in the Technical Preview, they’ve combined both Bing and HERE maps, all of the glorious detail is there, and on top of that, routing of public transport works!! I live outside of Tokyo and the detail of the new Map application is splendid. I work adjacent to Tokyo Station, so will have a look see on Monday.
The same applies to maps for Korea (see above), pointing towards another turning point for the OS in the region on its journey to relevance.