Asano clan is a Japanese kin group of the Sengoku period and Edo period.
The Asano are descendants of the Emperor Seiwa (850-880), of Minamoto no Yorimitsu (944-1021), and are a branch of the Toki family. Minamoto no Mitsunobu, descended from Yorimitsu in the 4th generation, settled at Toki (Mino) and took the name of that place. The Toki were hereditary shugo (Governors) of Mino province until the 16th century.
The Asano name is perhaps most well known as a result of the story of the Forty-seven Ronin, whose lord was Asano Naganori, the head of a branch of the family enfeoffed at Ako (Harima Province, 53,000 koku).
The Asano were tozama daimyō, or "outside lords", meaning that they held no hereditary ties to the Tokugawa shogunate. They were thus burdened with various responsibilities and obligations to the shoguns to a greater extent than many other lords. Nevertheless, their home castle city of Hiroshima was a major port, and they ruled over Aki and Bingo Provinces, their holdings totaling 426,500 koku.