<P> Though Napoleon Bonaparte started his military career in artillery, campaigning in the Napoleonic Wars generally emphasized movement rather than static entrenchment . But innovations in trench warfare became more prominent in the course of the 19th century . </P> <P> In the New Zealand Wars (1845 - 1872) the indigenous Maori developed elaborate trench and bunker systems as part of fortified areas known as pa, employing them successfully as early as the 1840s to withstand British cannon, muskets, and an experimental poison - gas mortar . These systems included firing trenches, communication trenches, tunnels, and anti-artillery bunkers . British casualty rates of up to 45 percent, such as at Gate Pa in 1844 and the Battle of Ohaeawai in 1845, suggested that contemporary firepower was insufficient to dislodge defenders from a trench system . </P> <P> The Crimean War (1853 - 1856) saw "massive trench works and trench warfare", even though "the modernity of the trench war was not immediately apparent to the contemporaries". </P> <P> North American armies employed field works 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 also featured in the Paraguayan War (which started in 1864), the Second Anglo - Boer War (1899 - 1902), and the Russo - Japanese War (1904 - 1905). </P>

The usual tactic of trench warfare was to