堀Hori (moat)

A moat is a deep, broad ditch dug around a castle, fortification, building or garrisoned town, either dry or filled with water, historically to provide the site with a preliminary line of defence, particularly against siege engines. Moats typically deny all direct land access except at a few narrow locations traversed by drawbridges, bridges or causeways, into which a siege will be funneled and thus easier to defend against.

In some places, moats evolved into more extensive water defences, including natural or artificial lakes, dams and sluices. In older fortifications, such as hillforts, they are usually referred to simply as ditches, although the function is similar. In later periods, moats or water defences may be largely ornamental. They could also act as a sewer.

Text from Wikipedia: Moat — CC BY-SA 4.0. Read more on Wikipedia →