Spoiler (click to reveal)
I'm trying to think about the discussion going on in other threads about when it's possible to 'run out' of objectives. If I'm remembering right, the Monitor action is the minimum you need to be able to recon east asia, since even if you don't know what boxes to check you could technically just check a bunch and find the recon.
What's the trigger for unlocking the Monitor action? Anyone remember? I don't remember what caused us to find it.