[ahazred8ta]

> The Japanese somehow had intel on a secret new weapon

Yes. They did. The Mexico branch of the Japanese espionage service knew about the Trinity test in advance and sent agents to collect fallout to analyze. They already knew before Hiroshima that we had a working atomic bomb. They underestimated our isotope separation production capacity because their own U-235 isotope separation plant was behind schedule. There have been books written about the Japanese atomic bomb project. The day after Hiroshima, the Japanese government announced "We also have atomic bombs and we will use them against the invasion forces." They were expecting the war to last another year. The head of the Japanese atomic bomb project said that his military boss expected the war to last another year.