堀

moat

canal

canal

outer moat (of a castle)

irrigation ditch

kobori

man-made water channel (e.g. round a castle)

dry moat

canal

digging deeply (below the surface)

to remove obstacles in the way of one's objective

to be clear of obstacles in the way of one's objective

moat

inner moat

to dig up messily

pocket gopher

ascending trench or pathway cut into a naturally-occurring slope

fish pond (artificially stocked)

side of a moat