The Yakovlev Design Bureau, officially known as JSC A.S. Yakovlev Design Bureau, is an aerospace and defense manufacturer based in Moscow, Russia. Founded in 1934 under the leadership of Alexander Sergeyevich Yakovlev, the company specializes in the design and production of civil and military aircraft, with a particular focus on fighter planes. The company was acquired by Irkut Corporation in 2004 and later merged with Mikoyan, Ilyushin, Sukhoi, and Tupolev to form the United Aircraft Building Corporation in 2006. Despite its diverse range of products, Yakovlev is perhaps best known for its highly successful line of World War II-era piston-engined fighter aircraft.