A fortress garrisoned by heavy troops is hard to break through.
Tips
usage
Almost always paired with verbs of placement: 部署重兵 (deploy heavy troops), 重兵把守 (heavily garrisoned), 屯重兵 (station strong forces). The 重 (zhòng, 'heavy/important') here means a sizable, elite force — not literally heavy in weight.
mistakes
Don't read as chóngbīng (重 has two readings). The military sense is always zhòngbīng (heavy/serious), never chóngbīng (which would mean 'repeated soldiers' and is not a word).
