The arquebus became the most important missile weapon in the latter half of the 16th century and the great daimyo could field thousands of ashigaru armed with these firearms thus changing the way warfare was conducted in Japan forever.

Within two or three years, according to a Portuguese observer, the Japanese had succeeded in producing several hundred of these firearms and by the 1550s the arquebus was commonly deployed on the field of battle. Japanese gunsmiths founded schools to pass on this recently acquired knowledge and they even developed some improvements of their own over the European model. Unlike the European arquebus the Japanese version had bores standardised to only a few sizes so that it was easy to mass-produce the bullets. This enabled for bullets to be conveyed to the battlefield in huge quantities so that the arquebusier could be well supplied.

Although the technology and effect of the arquebus was realised the same could not be said for their use in battle. They were slow to reload and could always be outshot by archers who would also be more accurate. It was therefore necessary to train the users of arquebuses, the arquebusiers, properly but it still took time for them to be utilised to their fullest effect. Although it took a relatively short amount of time to train someone to use an arquebus - a great advantage over the longbow which required great strength to use - speed of loading had to be practiced, married to the discipline needed to successfully carry out bursts of volley fire that is one rank firing, followed by another whilst giving time for the first to reload and fire again, and so on. This would keep up an almost continuous rate of fire although usually with more than just two ranks. This meant that pride of place at the front of the battle would have to go to the ashigaru arquebuses which was traditionally the preserve of the samurai. But for firearms to be effective the guns had to be at the vanguard of the army. This social etiquette, however, wasn't followed by the warrior monks of the Ikko-ikki who were the first to use controlled volley fire on a mass scale in Japan five years before the battle of Nagashino. The warrior monks of Ishiyama Hongan-ji deployed 3,000 arquebusiers who forced the main body of Oda Nobunaga's army back after their fortress had come under attack. It comes as no surprise that Nobunaga should then use this volley fire tactic to such devastating effect at Nagashino five years later against the Takeda clan. The Japanese invasion of Korea in 1592 saw many thousands of arquebusiers being used in the campaign and the firearm became the most important weapon a soldier could take with him.

The arquebus could be fired from the shoulder and did not need to be mounted on a rest like the heavier musket. It consisted of an iron barrel fitted onto a wooden stock and on the right of the stock was a brass serpentine which was linked to a spring that dropped the serpentine when the trigger was pulled. The serpentine contained the ends of a smouldering match or fuse which dropped into the firing pan when the trigger was pulled and in turn ignited the priming gunpowder. The match itself was either wrapped around the stock of the gun or the arquebusier's wrist. To prevent premature explosions the pan was closed by a brass sliding cover which swung back at the last moment. When the pan was ignited and the bullet began its journey through the barrel to its target, the recoil was quite considerable as was the smoke produced. To reload the gunner poured some gunpowder down the barrel and rammed it down with a ramrod. Next the bullet was rammed home and then the firing process could start all over again.

The weather could be a major factor as so often when it rained the fuse would get wet thus making the weapon unable to fire. To combat this fuses were boiled in a chemical solution or another idea was to have a small box fitted over the touch hole in effort to shelter it. Another problem was that ramrods could break so each arquebusier usually carried with him two or three spares. If these broke then the gunner could use the even sturdier version carried by the ko gashira. There was also the danger of fitting the fuse badly into the serpentine because the fire could go out. Usually an arquebusier carried a spare fuse if this happened. Another danger was the barrel becoming fouled and scorched after firing five or six shots. This meant that bullets could potentially get stuck and the rate of fire would suffer as a result. Sometimes the force of the explosion would dislodge the fuse and the Japanese attempted to solve this problem by inserting a small bamboo peg through. But this was very unsafe because the risk of a premature discharge was greatly increased. The only way to prevent this from happening was to remove the fuse completely.

Modern tests showed that a good gunman could load, prime, aim and fire in just fifteen seconds. However, the smouldering fuse had to be kept out of the way of the pan so this reduced the firing time between twenty and thirty seconds. An inexperienced gunner could only hope to complete the sequence in one minute. The introduction of cartridges greatly improved the rate fire. To aid firing in the dark the top end of the stock was fitted with a length of cord so that the arquebusier could gauge the elevation.

Further Reading

Nagashino 1575 - Stephen Turnbull

Samurai (World of the Warrior) - Stephen Turnbull

Warriors of Medieval Japan - Stephen Turnbull