I don't really get the meaning of the sentence below. I'd really appreciate it if you help me understand it. And it would be helpful if you paraphrase it in the simplest way. Thanks in advance.

"Japan has made these moves far easier for players from the ASEAN region by a ‘visa exemption’ that allows nationals from most of the zone to be counted outside the ‘three plus one’ cap that otherwise applies, and that’s seen several others enjoy brief, if unsuccessful, stints across the top three flights of the country."