Campaign 74B (2 February–30 April 1971) was a major combined arms offensive by the People's Army of Vietnam (PAVN) during the Laotian Civil War. The Communist offensive, if successful, would knock the last remaining fighting troops of the Kingdom of Laos out of the war, ensuring the Vietnamese conquest of Laos. The PAVN 316th Division—reinforced by artillery, tanks, and sappers—attacked during a period of slackened tactical air support for General Vang Pao's guerrilla army; Operation Lam Son 719 was being waged at the same time. Having captured the highly strategic Plain of Jars during Operation 74B, the Communists attackers managed to penetrate deeply enough to fire upon the main guerrilla base at Long Tieng.