Sō Yoshiyori

was a Sō clan daimyō (feudal lord) of the island domain of Tsushima at the end of Japan's Edo period.

Yoshinori was the head of the Sō clan from 1842 through 1862.

Black ships Sō Tsushima-no-kami was a senior member of the Imperial Commission which was delegated the responsibility of meeting with Commodore Perry and his men on March 8, 1854. He sat next to Daigaku-no-kami Hayashi Akira in the conference meeting.

March 8, 1854 (Kaei 7, 10th day of the 2nd month) : Commodore Perry returned to Edo Bay to force Japanese agreement to the Treaty of Kanagawa; and the chief Japanese negotiator was Daigaku-no kami Hayashi Akira, who was known to the Americans as "Prince Commissioner Hayashi".

In the context of this unique negotiation with the Americans, Yoshinori's rank was considered secondary only to Hayashi. Perry construed his counterparts as an Imperial Commission consisting of five Commissioners with supporting staff and military support: Hayashi Daigaku-no-kami; U-dono Minboi-shiogū – Americanized as "Udono, member of the Board of Revenue"; "Matsusaki Michitaro".