Along with advancements in communication, Europe also continued to advance in military technology. European chemists made new explosives that made artillery much more deadly. By the 1880s, the machine gun had become a reliable battlefield weapon. This technology gave European armies an advantage over their opponents, as armies in less-developed countries were still fighting with arrows, swords, and leather shields (e.g. the Zulus in Southern Africa during the Anglo-Zulu War of 1879). Some exceptions of armies that managed to get nearly on par with the European expeditions and standards include the Ethiopian armies at the Battle of Adwa, and the Japanese Imperial Army of Japan, but these still relied heavily on weapons imported from Europe and often on European military advisors.