Myanmar coup: What is happening and why?

From what I have listened to and read from the BBC, they have turned far left. But, this article appears to lay out the situation fairly well.
My education of this part of the world is limited. But the last few years, I have noticed China attempting to control shipping lanes. I have to wonder, if this coup is related to that issue. Perhaps, it is deeper. A distain for civilian rule and a country that would have aliened themselves with American trade?
If anyone here on RP can address this topic, that would be great. I look forward to gaining a greater understanding of this part of the world.