Japan source Data: Licence of cyberjapandata.gsi / ZIP areas

Hi,

I have a question about tracing objects on Japanese areas. There are the new areal pictures also being integrated into the "in browser editor" iD (Japan GSI ortho Imagery). The tiles are being addressed using the following link http://cyberjapandata.gsi.go.jp/xyz/ort/{z}/{x}/{y}.jpg . On the same webpage there are also tiles for precise maps. These are connected by the link http://cyberjapandata.gsi.go.jp/xyz/std/{z}/{x}/{y}.png . Contrary to the areal images, these maps exist for all Japan, and are also available in higher zooming levels. On the webpage https://github.com/mapbox/mapping/issues/116 they are claiming to use this source for tracing.

I want to make absolutely sure, that this is legal. I'm rather astonished, because these are high quality maps, which represents a different level of source than just areal images. Does anyone of you have experience with this source?

I have another question about Japanese data sources. It would be very useful to assign the areas for ZIP codes (postal codes). In Japan most (or all?) addresses are a combination of numbers and these areas and not streets and numbers (please correct me if I'm wrong). Therefore this information is essential. I only found one blog addressing this point "https://lists.openstreetmap.org/pipermail/talk-ja/2015-January/008707.html", not really coming to a conclusion. Do you have experience with that?

Thanks a lot and best regards Manuel