On the peninsula of Shandong in the south of China, knife-shaped coins called dao had been used since the 7th century BC. The currency of these knife coins was "huo," meaning "exchange" or "trade." More, we do not know: Neither how much 1 huo was worth, nor what purchasing power one knife coin had – quite a high one, in all probability. Towards the end of the 3rd century BC, new coins of the huo currency appeared. They were round with a square hole in the middle. These new coins were issued in denominations of 1, 4 and 6 huo – in small values, unlike the knife-coins usable for every-day trade.