two or four horses with a single draught pole measuring around 3 m long that was originally straight but later evolved into two curved shafts. At the front end of the pole there was a horizontal draw-bar about one meter long with wooden yokes attached, to which the horses would be harnessed. Wooden wheels with a diameter of between approximately 1.2 – 1.4 m were mounted on a axle and secured at each end with a bronze hubcap. Wheels of the Shang period usually had 18 spokes, but those of the Zhou period numbered from 18 to 26. Chariot wheels of the Spring and Autumn period (8th–7th century BCE) had between 25 and 28 spokes. The carriage body was around one meter long and 0.8 meters wide with wooden walls and an opening at the back to provide access for soldiers. With the arrival of the Spring and Autumn period (771–476 BCE) improvements had been made to the chariot's design and construction. The angle of the curved draw pole had increased raising the end of the pole. This reduced the amount of effort required by the horse pulling the chariot and increased its speed. The width of the carriage body had also increased to around 1.5 m allowing soldiers greater freedom of movement. Key components such as the pole, hubcap and yoke were reinforced with decorated copper castings, increasing the chariot's stability and durability. These chariots were variously referred to as "gold chariots" (金車), "attack chariots" (攻車) or "weapons chariots" (戎車). The Chinese war chariot, like the other war chariots of Eurasia, derived its characteristic ability to perform at high speed by a combination of a light design, together with a propulsion system using horses, which were the fastest draft animals available. Crew and weaponry Usually a chariot carried three armored warriors with different tasks: one, known as the charioteer (御者) was responsible for driving, a second, the archer (射) (or sometimes multiple archers (多射)) tasked with long range shooting. The róngyòu (戎右), whose role was short range defense, made up the third member of the crew. Weapons carried on the chariot consisted of close-combat and long range weapons. The most important close-combat weapon aboard the chariot was the dagger-axe or gē (戈), a weapon with a roughly three-meter shaft. At the end of the double-headed device there was a sharp dagger on one side and an axe head on