A simple basic yuan coin weighs about 6.1 grams, but there are different kinds & editions so the weights may vary, exg a yuan made of gold will be much heavier than one made of silver, which in turn is heavier than one made of nickle.
Answer: Horses. Riding on horses in battle or just finding a place to settle would have been much easier than walking. So, the were helpful in battle and they were helpful to nomads.
