His ears are missing, his fingers are deformed and he is weakened by chronic illness, making Akihiro Takahashi a living testimonial to the horrific results of the atomic bomb that exploded over Hiroshima half a century ago.

Mr. Takahashi, who was 14 at the time, became director of the Hiroshima Peace Memorial Museum and a campaigner against nuclear weapons. Like many Japanese, Mr. Takahashi argues that the United States broke international law and all principles of humanity by using nuclear weapons.

A debate about the ethics of the bomb has raged since it was dropped. In recent months the dispute has been amplified by controversies over a postage stamp depicting Hiroshima and over an exhibit about the bombing at the Smithsonian Institution.

Sipping an iced green tea, Mr. Takahashi responded to some of the arguments that Americans often raise to justify the use of the atomic bombs on Hiroshima and Nagasaki. Mr. Takahashi spoke with Nicholas D. Kristof, Tokyo bureau chief of The New York Times, and his answers were translated by The Times.

Q. You say that the atomic bombing was inhumane and a violation of international law. But some 55 million people died in World War II, all horribly, and less than one-half of 1 percent died at Hiroshima. What is so special about the victims here?

A. This was a special type of attack, with a weapon that used radiation. One bomb alone destroyed a large city, in one moment. By 1950, about 200,000 people had died in Hiroshima, and in total in Hiroshima and Nagasaki, more than 300,000 people died. So maybe the number of people who died is small in the overall total of World War II deaths, but there were special features of this attack.

Subscribe to The Times to read as many articles as you like.