It appears that Ryūjō was manufactured as an order from an independent blossoming daimyo's navy to Scottish shipbuilding firm Alexander Hall & Sons Ltd. in 1864. It was completed in 1869 and originally equipped with eight 64lb guns and two 100lb guns, with which it served under the name "Josho maru" for an extremely short time period before it was integrated into the new Imperial Japanese Navy. It served as a flagship for eight years, and remained in service for a total of 39 years, where it received a retrofitting later in it's life with six new 64lb Krupp guns while in service as a naval gunnery training vessel between 1893 and 1908.
Due to the ship being manufactured in Scotland, I'm left to figure that the weapons are probably of British ancestry. In particular, the original outfit of eight 64lb weapons to be RML 64 pounder 64 cwt guns. However I'm unsure, since said weapons were normally reserved for British Imperial vessels I'd think, and I'm skeptical that a private shipbuilding firm would have access to weapons like that to reproduce and sell overseas. The 100lb guns I suspect to be the RBL 7 inch Armstrong, but I'm also skeptical of it's inclusion for the very same reason. Both weapons were only a few years old and relatively new and cutting edge at the time of Ryūjō's construction. Yet the British manufactured several ships for the Japanese, many who actually did use the 7 inch Armstrong gun(abet much later), so I thought I must've assumed correctly.
However at the precipice of my confusion, I have no idea what 64lb Krupp weapons were outfitted on the ship in it's later days. I can't find any record of a Krupp naval gun, or any Krupp gun for that matter produced in the time period with that specific projectile weight. So at this point I became very confused. I noticed that the Krupp gun managed to have the exact weight as the previous gun it was replacing, so I began to contemplate why that would be.
Did Ryūjō already have those Krupp guns and just get her weapons reduced to six?
Did Ryūjō use antequated Krupp guns with the same shell which were updated to a newer gun that shared it?
I looked deeper and found a page on worldlibrary.org about her under the name "Jho Sho Maru" which had different information than Wikipedia(which every other website copied). It listed her as having 2 × 6.5 in (170 mm) guns and 10 × 5.5 in (140 mm) guns, it is again an entirely different set of information.
Wikipedia and most other sources state she had six Krupp 64 pounders even though this is obviously her later armament.
Aberdeenships, a website based in the hometown where she was built, lists her as having two hundred pounders and eight 64 pounders.
And worldlibrary lists her as having two 170mm and ten 140mm guns.
As such, you can see why I bear my immense confusion and curiosity. I'm at a loss about what this ship actually was armed with or where to even search for such information. Since everyone here seems to be very knowledgable and nice, I figured I'd ask since I stopped by. Thank you in advance.