"Half and two" coins are the most widely used ancient coins during the Warring States and Qin and Han dynasties, which are divided into pre-Qin half and two (Warring States half and two), Qin half and two and Han half. Generally, the half and half of the pre-Qin period before 220 BC is called the "Warring States and half and half", and the half and half of the Qin period after 220 BC after the Qin Shihuang unified the six countries are called the "Qin and half and half". After Qin Shihuang unified the six states in 221, the currency system was unified, with gold as the upper coin and copper as the lower coin. Copper coins were named "half two" and later generations called them "Qin half two". Since then, China's copper coins have obtained a fixed form of round outside and square inside, which has continued until the early years of the Republic of China. So, how much is Qin half two worth? After the unification of the coins, Qin Shihuang implemented a square hole round half coin with a diameter of 2.5cm-2.8cm and a weight of 3-6g. Its size was moderate and easy to carry and trade. After the casting, it quickly developed and circulated, and soon became the main currency after the annexation of the six countries. At that time, for the market demand and cast half a small money, the diameter of 1 cm -1.5 cm, weight 0.2 grams -0.4 grams of three, after more than 2000 years of vicissitudes spread.