Maybe on of the greatest but least known feats of vernacular building in Japan are the hundreds of stone "boar walls" (猪垣 or シシ垣) found mostly overgrown on the edges of rural villages all over the country, some up to a hundred kilometers long and two meters tall. 
Built to protect farms and fields from destructive boars, they led to many villages in the 17th-19th centuries look like fortified castle towns. Thousands more were built of wood or compacted earth, or dug out as ditches but few remains of these can be found today.
The effort to build and maintain these must have been unbelievable. Entire villages organized regular wall building days with mandatory participation. Often the walls were combined with traps were boars could be dispatched relatively easily with spears.
Up until the 20th c., boars posed such a threat to human life that guns were seen as an essential farming tool. A typical village had access to typically one rifle per two households. These days electric fences are cheap and easy, but as hunters diminish boar populations explode.
