Union and Confederate armies employed field works and extensive trench systems in the American Civil War (1861–1865) — most notably in the sieges of Vicksburg (1863) and Petersburg (1864–1865), the latter of which saw the first use by the Union Army of the rapid-fire Gatling gun, the important precursor to modern-day machine guns. Trenches were also utilized in the Paraguayan War (which started in 1864), the Second Anglo-Boer War (1899–1902), and the Russo-Japanese War (1904–1905).