The sun-mirror (Chinese: 陽燧; pinyin: yángsuì) was an ancient Chinese burning-mirror that concentrates sunlight to ignite tinder, and the moon-mirror (Chinese: 方諸; pinyin: fāngzhū) was a device that collects nighttime dew by condensation. These two bronze implements are literary metaphors for yin and yang, associating the "yang-mirror" yangsui with the sun (a.k.a. tàiyáng 太陽 "great yang"), fire, dry, and round, and the "yin-mirror" fangshu with the moon (tàiyīn 太陰 "great yin"), water, wet, and square.