From
曾国藩's (1811-1872) doctrine
扎硬寨,
打呆仗 ('pitch strong camps, fight dogged battles'): the
湘军 would halt before sundown and dig trenches, walls and moats around every camp before resting. The slow, attritional style eventually wore down the Taiping rebels and is still cited as a metaphor for patient, disciplined strategy.