| Surname: | Azai |
| Surname Nihongo: | 浅井 |
| Image Size: | 140px |
| Image Caption: | The emblem (mon) of the Azai clan |
| Home Province: | Ōmi |
| Titles: | Daimyō |
| Founder: | Azai Sukemasa |
| Final Ruler: | Azai Nagamasa |
| Dissolution: | 1573 |
| Ruled Until: | 1573, Azai Nagamasa commits seppuku |
The, also rendered as Asai, was a Japanese clan during the Sengoku period.
The Azai was a line of daimyōs (feudal lords) seated at Odani Castle in northeastern Ōmi Province, located within present day Nagahama, Shiga Prefecture. The Azai originated in the early 1500s and claimed descent from the Hokke branch of the Fujiwara, a powerful clan in Japan from the Heian period to the Kamakura period.[1] Initially, the clan were vassals of the Kyōgoku, but gradually emerged as independent daimyōs in northern Ōmi.[1] However, Azai domains were soon conquered by the Rokkaku and the clan was forced into becoming their vassals. Azai Nagamasa became head of the clan in 1560 and successfully fought against the Rokkaku and Saitō Tatsuoki for independence by 1564. The Azai were long-time allies with the Asakura clan of Echizen Province who had assisted the clan in securing their independence. In 1570, Nagamasa joined the Asakura in their opposition to Oda Nobunaga, his brother-in-law and ally, to honour their alliance. The Azai were defeated by Nobunaga at the Battle of Anegawa in 1570, and all but eliminated when Nobunaga conquered Odani Castle and Nagamasa committed seppuku in 1573.[1]