A burlap sack filled with sand or soil. They're used for flood protection, military fortification, and as a "ballast":http://en.wikipedia.org/wiki/Ballast.

h4.See also

* "Wikipedia article":http://en.wikipedia.org/wiki/Sandbag
* [i]sandobaggu[/i] - a "wasei-eigo":[https://en.wikipedia.org/wiki/List_of_gairaigo_and_wasei-eigo_terms] referring to [[punching_bag|punching bags]]
土嚢 沙袋