"The arquebus was a European matchlock gun that was adopted by Asian cultures in the sixteenth century. When Portuguese explorer, Fenrao Mendes Pinto, accidentallly landed on the small island of Tanegashima in the Japanese archipelago in 1543, he introduced members of the Shimazu clan to the arquebus, and altered Japanese warfare forever. Within ten years, Portuguese guns could be found on every battlefield in Japan.
Despite the advantages of requiring smaller ammunition, and having a jarring psychological effect on its targets, the arquebus had many disadvantages. It was slow to reload, leaving its user at the mercy of archers firing at a much faster rate. It was also horribly inaccurate. Training to use the weapon was required, but this took time. However, once the training was complete, the arquebus proved to be a frighteningly lethal weapon, especially once the rate of reload was shortened by the development of volley-fire tactics.
Japanese Ikko-Ikki warrior monks were the first to use controlled volley-fire in battle, unleashing 3,000 arquebusiers on the body of Oda Nobunaga’s army before the Battle of Nagashino in 1575. With the strength of their new weapon, the monks were able to repel the daimyo’s forces and hold the castle. It was such a stunning display that by 1592, when Toyotomi Hideyoshi invaded Korea, the arquebusier was the primary weapon used by Japanese soldiers in the attacking army.
The Chinese began to use the arquebus at about the same time as the Japanese, although it is not as well recorded. It is generally believed that early Chinese firearms were based on designs taken from the weapons used by Japanese wokou pirates, who in turn had copied the designs of the Portuguese. Once the gun was introduced to the Chinese it became a standard issue. In 1558, Chinese gunsmiths manufactured a total of 10,000 guns for the Chinese Imperial Army."