The two samurai swords were one for Japanese tribute and the other for Ryukyu tribute, but Ryukyu was also estimated to have been bought in Japan. The handle of both knives is written with shark skin, in fact, strictly speaking, this pearl fish skin is not the skin of a shark, but the skin of a stingray. Stingray is a fish mainly produced in Southeast Asia and the southeast coast of China, but the ancients classified both stingray and shark as mackerel, and their skins are called mackerel skins, so the museum's explanation is not wrong. This fish skin is not only good-looking, but also more obvious than the general shark skin particles, more non-slip, so shark skin is generally used in the sheath of the knife, stingray skin is used in the handle. Stingray was rare in the late Edo period, so it is a very valuable decorative material for the handle. In addition, the Japanese tribute to this sword is also very special, unlike the ordinary samurai sword with a hollow disc. I have not studied Japanese samurai swords specifically, and I am not sure whether there is such a sword in the samurai sword, and I guess that it may be a fusion of Japanese swords and Chinese swords
