Yūkawa Cannon Series

Yūkawa Cannon (Series)

  The Yūkawa were a series of smoothbore high caliber field artillery pieces and naval guns developed in Japan by Shigeru Yasuda and his team in 1589. It's performance and versatility (It was able to fire ball, shell, canister, and Grapeshot) allowed it to replace and in sometimes outdo the contemporaries of the time, it also had the advantage of being a homegrown option for the Japanese who prior had to usually buy cannons from other powers.

Characteristics

  The Yūkawa does not refer to any single cannon, but was instead a series of different types of cannons with some traits in common. Consistent throughout all of the Yūkawa series was a smoothbore, Muzzleloading mechanism, and constructoin. The Cannon would be cast out of either Brass or Cast Iron in one homogenous shape, the bore then would be drilled out via a Lathe and be tested. All of the Yūkawa series could fire Ball, Shell, Canister, and Grapeshot. The variants being the 4.5 Kan (6 pound) Yūkawa, 1.5 Kan (12 pound) Yūkawa, Yūkawa Naval 3 Kan (24 pounder). All 3 of these would see much use in the battlefield.

History and Development

  On 1588 January 3rd, Directly after Takeshi's victory in unifying Japan he immediately sought to take back the pacific from the major European powers of the time, however he was smart enough to know that attacking at this state with a tired army and outdated equipment would be suicide for the already shaky nation. Looking over many of his victories he realized the key role that long range artillery had in many of them and sought to not only have more guns but make better ones. He looked at captured ones from the armies of Totoyami and Tokugawa and found them adequate however he wanted better, Takeshi wanted not only cheaper cannons, but better ones, bronze was nice, however pricey, and he wanted a quality cannon that could be easily manufactured, at the head of the project was Shigeru Yasuda and he was given this hefty task and immediately go to work.   The new cannons would have to hold bigger powder loads than the previously made small 2 pounders. Breechloading swivel guns were too unreliable and were not able to take bigger powder loads, and so all research went into making new muzzle loaders. With that decided the material came up. Brass was rust free, stronger, and lighter for the same strength however it was too expensive. Most efforts would go into making Brass cheaper and easier to work with, however due to costs other efforts did go into making cast iron cannons better. One advancement they would make was instead of having the bore in the cast, they would cast it solidly and then drill out the bore, this improve structural integrity and reliability. In April 8th a couple months after research had begun they had the first prototype, a 6 pounder brass cannon with a bore of 8cm and a barrel length of 2 meters. Takeshi and Yasuda were in attendance for the field tests. The target was the now dormant Ōkagi castle. Simple cast iron cannonballs were used, and to great effect many of the walls splintered and broke. Takeshi was happy with the performance for its use as light field artillery, however asked for a slightly bigger version, he proposed a cannon with a shell of 1.5 Kan or 12 pounds. Yasuda quickly made the new cannon simply by upsizing the existing one and the Yūkawa cannon was born.   Between 1590 and 1592 in tandem with field cannon development Takeshi asked Yasuda to make a naval gun. He obliged and got to building new versions of both the Yūkawa and Yasuda Rifle for naval use. He was given an old warship to test his designs on and find what worked. The first thing he did was ditch the 2 large wheels and replace it with a 4 wheeled carriage, as they were easier to move in the confined space of what was going to be the Geobukseon. He began upsizing the Yūkawa, and developed the new Yūkawa Naval 3 Kan (24 pounder).

Usage

Much like its contemporaries it was used much like any other muzzle loading cannon. Powder and rounds were inserted through the muzzle and packed in, customarily the powder was contained in a cloth or paper bag. A small hole in the breech would have a piece of cloth or rope and when the cannon was fired the piece was lit, the cloth would start a fire in the powder packed into the breech and the projectile would fire. After the round was fired the worm was used to clear out any embers made by the powder, another member would then use a slightly damp sponge to both cool the barrel and clear out any embers, another member would shove a dry sponge through the barrel to clear out any excess water, and finally the reload would be performed. Ideally a cannon crew would usually consist of 8 members, 2 loaders, 1 with the damp sponge, 1 with the dry sponge, 1 with the worm, 2 men manned the breech, and one officer who's job would be spotting. A crew would usually have 4 more member who's job was to handle horses and equipment. Each member was cross-trained, and could perform each other's duties in the case others are incapacitated.