Previously unpublished letters by Albert Einstein to a Japanese pen pal show the physicist to be torn and defensive over the atomic bombings of Hiroshima and Nagasaki which became possible partly through his genius.
Einstein smoking his peace pipe, although not without reservations
The widow of Seiei Shinohara, a philosopher and German-Japanese translator who corresponded with Einstein in the last years of the famed German scientist's life, has chosen to go public with the letters on the 60th anniversary of the world's only nuclear attacks.
Einstein's opposition to nuclear warfare has already been documented, but his letters to Shinohara also show him defending himself on a personal level and trying to reconcile his pacifism.
The correspondence began in 1953 when Shinohara sent a letter to Einstein criticizing the physicist over his role in developing nuclear weapons.
Einstein responded by hand on the back of the typed letter, beginning his rebuttal without bothering to offer greetings.
A defensive genius
"I have always condemned the use of the atomic bomb against Japan but I could not do anything at all to prevent that fateful decision," Einstein wrote in German to Shinohara in a letter dated June 23, 1953.
Theory of relativity? A piece of cake (for Einstein, that is)
2005 has been designated as the "Einstein year" to mark the centennial of Einstein's theory of relativity and his overall contribution to physics. He argued that distance and time are not absolute, leading to his most famous formula, E=mc2, essential for the development of the atomic bombs dropped on Japan by the United States.
The Hiroshima bombing killed around 140,000 people -- almost half the city population at the time -- immediately or in the months afterward from radiation injuries or horrific burns.
More than 70,000 more people died three days later in the bombing of Nagasaki. After six days Emperor Hirohito went on the radio for the first time to announce the surrender of Japan, which since the war has campaigned to abolish nuclear weapons.
"The only consolation, it seems to me, in the development of nuclear bombs is that this time the deterrent effect will prevail and the development of international security will accelerate," Einstein wrote in another letter.
A pacifist who believed in the just war
But Einstein, whose Jewish origins led him to flee Germany in 1933 for the United States, after Adolf Hitler came to power, also said that war was sometimes acceptable.
The force of nuclear destruction: Hiroshima, 1945
"I didn't write that I was an absolute pacifist but that I have always been a convinced pacifist. That means there are circumstances in which in my opinion it is necessary to use force," he wrote.
"Such a case would be when I face an opponent whose unconditional aim is to destroy me and my people," he said.
"Therefore the use of force against Nazi Germany was in my opinion justified and necessary."
Shinohara, who studied philosophy in Germany before returning to Tokyo in 1947, died of a stroke in 2001 at age 89. His letters have since been kept in private by his widow, Nobuko Shinohara.
The correspondence ended in July 1954, a year before Einstein died, dashing Shinohara's dream to meet the physicist face to face.
"My husband first sent the letter with anger and I guess Dr. Einstein replied with annoyance," said Shinohara, 80.
"But later Dr. Einstein and my husband formed a friendship through exchanging letters," she said.
Several museums have already made requests seeking the letters for their collections, according to Yutaka Sakuma, a lawyer handling the papers.