Shirakawago in Gifu Prefecture and Gokayama in Toyama Prefecture are registered as World Heritage. The houses in these small vilages have thatched triangle gabled roof – the shapes seen only in this heavy snowfall area.
The shape of the roof is regular trianble. The slope is steep so that heavy snow does not stay on the roof during the winter. The vilagescape with small thatched roofs are very nostalgic and picturesque although it should be very hard to maintain and mend these houses.
UNESCO explains about this site.
For travel information, visit the page of japan-guide.com.
Japan National Tourism Organization also has some info.