Japan was sending out peace feelers thru the Swedish Embassy weeks before the bomb dropped.
It should be “some parts of the Japanese government” were sending out feelers...John Toland’s book is an excellent one: “The Rising Sun: The Decline and Fall of the Japanese Empire, 1936-1945”
Here is an interesting document from the National Security Archives at George Washington University, dated July 24, 1945.
http://nsarchive.gwu.edu/NSAEBB/NSAEBB162/42.pdf
The key paragraphs are the last three, in which Ambassador (to Moscow) Sato (1) sent a long message home recommending the acceptance of any peace terms, including unconditional surrender, as the only way of preserving the Emporer and the State; (2) concludes that he may be alone in his quest for peace but that his conscience demanded that he pursue it; and (3) the Japanese War Council received his message, rejected it, and determined that “the war must be fought with all of the vigor and bitterness of which it is capable as long as the only alternative is the unconditional surrender.”
Given that the Japanese resistance got exponentially more rabid as we got closer and closer to the homeland, there is no rational way to believe they would ever surrender without a nuclear attack.