The fight against the proliferation of nuclear weapons is a very urgent topic for Pope Francis.

The Pontiff was officially invited to visit Japan by Prime Minister Shinzo Abe in June 2014. On May 2, 2018, Tomihisa Taue, Mayor of Nagasaki, sent a letter to Pope Francis signed by him and by the Mayor of Hiroshima, Kazumi Matsui, inviting him to their two cities, targets of atomic bombs in August 1945, leaving 110,000 dead instantly and at least the same number after being exposed to radiations.

The Japanese “understand the price of peace,” observed Monsignor Paul Richard Gallagher, the Holy See’s Secretary for Relations with States, at the end of his trip to Japan from January 28 to February 3, 2017.

In January last year, Francis issued a harrowing photograph taken in 1945 showing a young Japanese boy carrying his dead brother. The child, carried on the boy’s back, was killed when the United States dropped the Atomic bomb on Nagasaki. Francis, who has often spoken of the dangers of nuclear weapons, had written just four words on the back of the image: “The fruit of war.”

At the end of the audience on June 19th, greeting the English-speaking pilgrims, the Pope in particular addressed the Young Messengers of Peace of Hiroshima and Nagasaki, who had come to the Vatican from Japan. As a symbol of hope the elimination of nuclear weapons, Pope Francis also put out a flame lit from the ashes of the atomic bombing of Hiroshima, in 1945, during the general audience of March 20, in the presence of a delegation of Earth Caravan peace activists.

Last May, the Pope wrote two letters, promising his prayer for the citizens of Hiroshima and Nagasaki, in response to the Mayors and the Governor of the Hiroshima Prefecture, who invited him

Pope Francis not only condemned the use of nuclear arms but also their “possession,” in an address he gave in 2017: «Nor can we fail to be genuinely concerned by the catastrophic humanitarian and environmental effects of any employment of nuclear devices. If we also take into account the risk of an accidental detonation as a result of error of any kind, the threat of their use, as well as their very possession, is to be firmly condemned».

The journey to Hiroshima and Nagasaki marks the path toward the 2020 International Nuclear Non-Proliferation Conference.