The multi-national military attachés and observers who took part in the Russo-Japanese War were expressly engaged in collecting data and analyzing the interplay between tactics, strategy, and technical advances in weapons and machines of modern warfare. For example, reports evaluating the stationary battle at Port Arthur and the maneuver battle at Mukden demonstrate the lethality of modern warfare and foreshadow the combined effects of hand grenades, mortars, machine guns, and field artillery in World War I.