I watched a better documentary earlier this year, went into detail on how Ishawhatever came up with the idea of the false flag to seize Manchuria, but was dead set against the Mukden false flag, warning that it would start a war of attrition with China that Japan couldn't win.
By the time of Mukden, Mao had vanished with his fellow thugs, into the interior, on the Long March, and Chiang Kai-shek could turn his entire attention to the Japanese threat.
That war, and Tojo's rise led to Ishiwara's retiring to the country as Tojo rose precipitously to defacto supreme power. Tojo's next bright idea was to commit what is IMHO the biggest military blunder of all time, attacking the US -- didn't make sense then, doesn't now, and can't be made to make sense.
Both false flag operations were the bright ideas of local IJA commanders.
The Japanese military was the proverbial hammer, to them every problem looked like a nail. This was especially true of the Young Officers Movement, a radical group created in the early 30s to counter the rise of leftists in the military.
Many leaders in Japan knew the military was taking the nation to ruin, and many in the military itself, and they had no illusions about defeating the US. Yet apparently they could do nothing to stop it.
If you recall the link, I'd like to see that.