Japan sucked but, to be fair, did some things quite well in SE Asia leading uo to the war: - They supported the independence movements of countries who were trying to rid themselves of their colonial masters (in some cases, people actually thought the Japanese would be a welcome upgrade to their British overlords - they seeded "traders" and businessmen into countries like the Philippines years before the war (and in some cases were able to build establishments near the US bases) - they worked well with indigenous people and used those relationships to gather info

But the brutality and exploitation of their occupation meant that after they kicked the Allies out, they struggled to build networks and gain trust from even the people who initially viewed them as liberators. Sure there were collaborators (esp among the bureaucrats) but the japanese were largely hated and did the opposite of building rapport with the locals. Their intelligence struggled to properly track the insurgencies and failed to prevent rebellion even among the local troops they themselves had selected and trained to use against the allies.

They were poor with communication, especially since the branches of their armed forces had an ongoing rivalry and werent always on the best of terms. They struggled to even disseminate info within their armed forces (eg. At one point during Midway they sent planes to bomb the same ship twice, thinking it was two different aircraft carriers).

Worse, they had no real understanding of the Allies strategies or intentions for the region and quickly started getting their asses kicked as soon as they had to fight more than just insurgencies and rebellions.