Present:
Secretary of War
General Marshall
Mr. McCloy

Subject:
Objectives toward Japan and methods of concluding war with minimum casualties.

The Secretary of War referred to the earlier meeting with the Acting Secretary of State[Grew] and Mr. Forrestal on the matter of the President's speech[scheduled for May 31] and the reference to Japan. He felt the decision to postpone action now [on the warning to surrender] was a sound one. This only postponed consideration of the matter for a time, however, for we should have to consider it again preparatory to the employment of S-1.

The Secretary referred to the burning of Tokyo [by incendiary bombings on March 9 - 10 and May 23 - 26] and the possible ways and means of employing the larger [i.e., atomic] bombs. The Secretary referred to the letter from Dr. [Vannevar] Bush and Dr. [James] Conant on the matter of disclosing the nature of the process to other nations [the letter is described after this memorandum] as well as to Dr. Bush's memorandum on the same general subject. General Marshall took their letters and stated he would read them and give his views on their recommendations as soon as possible.

General Marshall said he thought these [atomic] weapons might first be used against straight military objectives such as a large naval installation and then if no complete result was derived from the effect of that, he thought we ought to designate a number of large manufacturing areas from which the people would be warned to leave - telling the Japanese that we intended to destroy such centers. There would be no individual designations so that the Japs [sic] would not know exactly where we were to hit - a number [of possible targets] should be named and the hit should follow shortly after. Every effort should be made to keep our record of warning clear [although no warning was given to Hiroshima before it was hit with the atomic bomb]. We must offset by such warning methods the opprobrium which might follow from an ill considered employment of such force.

The General then spoke of his stimulation of the new weapons and operations people to the development of new weapons and tactics to cope with the care and last ditch defense tactics of the suicidal Japanese. He sought to avoid the attrition we were now suffering from such fanatical but hopeless defense methods - it requires new tactics. He also spoke of gas and the possibility of using it in a limited degree, say on the outlying islands where operations were now going on or were about to take place. He spoke of the type of gas that might be employed. It did not need to be our newest and most potent - just drench them and sicken them so that the fight would be taken out of them - saturate an area, possibly with mustard, and just stand off. 

He said he had asked the operations people to find out what we could do quickly - where the dumps were and how much time and effort would be required to bring the gas to bear. There would be the matter of public opinion which we had to consider, but that was something which might also be dealt with. The character of the weapon was no less humane than phosporous and flame throwers and need not be used against dense populations or civilians - merely against these last pockets of resistance which had to be wiped out but had no other military significance.

The General stated that he was having these studies made and in due course would have some recommendations to make.

The Secretary stated that he was meeting with scientists and industrialists this week on S-1[the Interim Committee meetings of May 31 and June 1] and that he would talk with the Chief of Staff [General Marshall] again after these meetings and the General repeated that he would shortly give the Secretary his views on the suggestions contained in the letter above referred to.