Your average Japanese person was being lied to about the war and had no reason to doubt it until the B-29s and B-24s started hitting the home land in force. Japan had never been invaded, or attacked, aside from Doolittle (which was a shock for that reason). I think we launched some B-29s from China to hit Japan early in 1944 but the logistics of that was ridiculous, so it wasn't until Saipan and Tinian and Guam fell (mid-1944) that the bombing started, which was November 1944.
I guess by then they knew things were going badly, but not how badly. The Japanese armies were still deep into China in large numbers. I'm sure by early 1945 the average Japanese person was beginning to feel the pinch on food. The islands could have been starved into submission by 1946 entailing mass starvation into the millions.