A gorge in field fortification is the "unexposed side of a fieldwork",[1] typically the rear of an independent fieldwork or detached outwork in front of the main fortress or defensive position.
Straith describes three commonly used classes of field work: "works open at the gorge, works enclosed all round and lines."
He lists the following as works open at the gorge:[2] Closed works are the redoubt, star fort and bastioned fort.
[2] Gorges of 'half-closed works' were usually closed either by a parapet or stockade.
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