In 1863, the Russian Army had perfected a fulminatingmusketball that could explode when it hit a hard target and was designed to blow uppowder magazines or ammunition wagons. In 1867, they perfected an improved explosive musketball that would detonate on any impact after being fired, even soft targets like people or animals. Predicting the disastrous effect of such a discovery on diplomatic relations with their neighbors, Russia decided to negotiate a ban on the development, creation, and use of such weapons before a grisly arms race commenced. Upon the invitation of the Russian diplomat and statesman Prince Alexander Gorchakov, for the purpose of considering the existing rules of war, a conference of delegates met at Saint Petersburg, Russian Empire, in December 1868. The nations represented were Austria-Hungary, Bavaria, Belgium, Denmark, France, United Kingdom, Greece, Italy, the Netherlands, Portugal, Prussia, the North German Confederation, Russia, Sweden-Norway, Switzerland, the Ottoman Empire, and Württemberg. The United States, not considered a major power at the time, was not invited and took no part in the convention. Brazil ratified the agreement in 1869, as did Estonia in 1991. The delegates affirmed that the only legitimate object of war should be to weaken the military force of the enemy, which could be sufficiently accomplished by the employment of highly destructive weapons. With that fact established, the delegates agreed to prohibit the use of less deadly explosives that might merely injure the combatants and thereby create prolonged suffering of such combatants. The Great Powers agreed to renounce, in case of war among themselves, the use "by their military or naval troops of any projectile of a weight below 400 grams, which is either explosive or charged with fulminating or inflammable substances." While the declaration bans the use of fragmenting, explosive, or incendiary small arms ammunition, it does not prohibit such ammunition for use in autocannon or artillery rounds.
The influence of this declaration on international humanitarian law were elucidated in the Japanese case Ryuichi Shimoda et al. v. The State :
