Vertical Steel Bow Medieval Crossbows

At least during the 12th and 13th centuries Chinese steel crossbows appeared, first in Russia later on in Persia and further to the West. The steel bow here was placed vertically, not horizontally as in Hellenistic or Occidental medieval crossbows.

" K. HUURI.0 C , p. 230; R. SCHNEIDERD: ie Artzllerie des Mzttelalters.
See: A. N KIRPICHNIKOWD:i e Wurfartillerie des alten Russlands, p. 43 ff (in
Russian).

According to my book on Chinese weapons, these are the statistics of the Shenbi Nu (Divine-armed Crossbow) or Shenbi Gong (Divine-armed Bow):

Bow span - 98cm
Length - 140cm
String length - 77cm
Effective range - 150m
Maximum range - 370-460m
The penetrating power is such that the bolt can pierce two layers of iron lamellar even at the extreme range of 460m.

The arm of the bow is made of wood, but the arming foot-stirrup is made of steel and the crossbow mechanism of bronze. So it is not strictly speaking a steel crossbow - only a larger crossbow that is armed by stepping with one foot on a steel stirrup attached to the stock, while pulling the bow string with both arms. This was probably one of the first stirrup-armed crossbows in history, since the first depiction of a stirrup-armed crossbow is in the Wujing Zongyao, written around 1044. Before that, the crossbowman had to step on the bow arm with both feet while pulling the bow string, which could damage the bow arm and also allowed less use of leg power.

According to the "Mengxi Bitan" by Shen Kuo of the Song dynasty, the Shenbi Nu was invented between 1068 and 1077 by a man of the Xi Xia empire named Li Ding (but named as Li Hong in the Song official history). It came to the Song empire in the form of a tribute offering by the Xi Xia. The Song emperor was so impressed by the power of this crossbow that he ordered it to be manufactured by the imperial armouries as a standard weapon for the Song armies. The Jin (Jurchen) heavy cavalry, whose "Iron Pagoda" elite unit who wore two layers of iron lamellar, were said by the famous commander Wanyan Wushu to fear only two Song weapons - the pole-axe (which could be used by infantry to chop the legs of horses, as Yue Fei did), and even more than that the Shenbi Nu.

The famous Song general Han Shizhong developed an improved version called the Kedi Gong (Enemy-vanquishing Bow) in 1135, in the critical years after the fall of the Northern Song. Its maximum range increased to 553m, and it was extremely effective against Jin heavy cavalry.