Looking for GIS dataset of Japan which includes smaller areas

This is probably a late reply but I found a good source for all small scale block names for the entirety of japan. It's quite useful. http://geoshape.ex.nii.ac.jp/vector-adm/

I've spend most of the day also doing this. I noticed that Google Maps seems to split these areas based on even smaller polygons (see here). I think that they are doing this on the fly or something kind of like voronoi.

I think maybe the reason why there isn't a concrete dataset of the boundaries is because regions are set on a national level in Japan and so maybe the responsibility of designating smaller areas is ambiguous or seen as unnecessary? despite using the same character as town, machi is only a unit of address, not administration. I'm sure the shapefiles exist somewhere but I'm also not sure who would have them.

maybe Yamato Transport?

edit: a good phrase to use while searching is 地名データ

I found one which works for me. Maybe it will work for you

http://nlftp.mlit.go.jp/ksj/gml/datalist/KsjTmplt-N03-v2_3.html

According to OSM's wiki on Japan, OSM holds data for major and minor neighborhoods. You can download those data via the Overpass API by using the QuickOSM plugin from QGIS or by using the Overpass Turbo web application.

From the QuickOSM plugin, you can provide the required parameters in an interactive and quite intuitive GUI. The required key-value pair is

admin_level: 9

for major neighborhoods or

admin_level: 10

for minor neighborhoods.

If you would like to use the Overpass Turbo application, you can provide the following query:

<osm-script>
    <id-query {{geocodeArea:Japan}} into="area_0"/>
    <union>
        <query type="relation">
            <has-kv k="admin_level" v="9"/>
            <area-query from="area_0"/>
        </query>
    </union>
    <union>
        <item/>
        <recurse type="down"/>
    </union>
    <print mode="body"/>
</osm-script>

Of course, you can change Japan to a smaller area and change the administrative level by using v="10" instead of v="9" in has-kv k="admin_level".

Geospatial Information Authority of Japan

http://www.gsi.go.jp/ENGLISH/index.html

http://www.gsi.go.jp/kankyochiri/gm_japan_e.html

Check the National Land Numerical Information website. The website has most of GIS data at national scale at various levels.