Japanese Campervans are slightly different from European RVs or American Motorhomes. There are many narrow roads in Japan, so vehicles are smaller to accommodate this. Motorhoming in Japan is still a relatively new concept, so availability of units can be limited.
Compared to the large, fully equipped motorhomes you might find in the USA and Canada, Japanese campervans are small and compact. The vehicles are less than five metres long, the benefit of this being that they are classed as ordinary vehicles so they can stop and park in any parking lot. However, this also means you won’t get some of the home comforts you can enjoy in larger vehicles. The facilities on Japanese campsites are of a very high standard which more than makes up for this.