This is simply not true. The second bomb was dropped soon after the first to give the impression that we had plenty where that came from. In a bit of serendipity, a bomber pilot shot down over Japan was coerced into 'confessing' that America had 100 bombs and was producing more at a healthy pace. Had Japanese intelligence not threatened the pilot with death if he did not reveal how many bombs America had and how many it was producing, he would have continued to tell them truthfully that he did not posses any knowledge on these lines.
Instead, the deliberations about surrender were made with Japanese intelligence assuring the bigwigs that America had a formidable and growing arsenal of nukes. The American bluff worked better than anticipated.
All that information was in the thread you participated in, yet new information did not change your views. You also do not seem to recall that the Japanese had withdrawn all the regular army units from Manchuria to defend the home island, leaving a few colonial conscripts commanded by some of the less fortunate Japanese officers to defend Manchuria. If the opposing army leaves, yes, you can take a lot of territory quickly.