Any plane can land at any airport as long as the runway is long enough. There is no regulation saying that a 737 cannot land at a non-controlled airport. All of the commercial pilots that have had their training in the private sector have had to land at non controlled airports. I say all, but I'm sure there are some exceptions. Let's just say most. It is no big deal.
Here at our local airport, KLBX, there is no tower and there are four large jets that come and go every single day, even when the weather is IFR.
There is so little realistic understanding of aircraft and air travel due to the continued misrepresentation by the media and movies. There was the incident of the control tower guy falling asleep and the commercial flight had to land without the tower control. It was all over the news as though it was a miracle that the plane didn't just crash all over the place. As though a pilot cannot land a plane without the tower saying "Cleared to land 13R." That's all they do anyway. The pilot is still responsible for looking and seeing if the runway is really clear and ready to take the plane.
In IFR conditions there is still what's called the minimums. If you can't see the runway when you reach the minimums you are not allowed to land there. Again, there is an exception, but it won't be available at non-controlled airports because of the cost.
I don't know about Brazil or Japan or any other country. I fly in the US only, and most of it in Texas. You'd be surprised how many non-towered airports there are where you even have to turn on the runway lights from your plane at night.