You're welcome! And yeah… Definitely take care of your school matters first! :)
It's not that
they have high latency, but
communications between where you are an Japan have high latency. For example, I have relatively little latency between myself and most Japanese players of the game, but I'll have higher latency playing with those in the midwest or eastern US. The internet is only global because of all of the networks and international communications backbones that are connected together.
Whenever you're communicating with someone in Japan over the internet (like playing Splatoon), the data has to physically travel around the world. And in your case, seeing that you're in Argentina from your profile, it's a much longer trip for you than me.
I'm not all that far away from one of the ends of the
Japan-US network of undersea cables, so no biggie for me. However, for you, there's basically three routes for your data to get to/from Japan. The shortest route is for it to travel up the Atlantic into the eastern US, across the US to California, and then to Japan via the same Japan-US network. The longer ways are for it to head through the Mediterranean, either by heading up to the Virgin Islands and traveling across the Atlantic to Spain, or by traveling across the Atlantic from Brazil to Senegal and then Portugal. From the Mediterranean it then would either head into and through Russia and then Japan, or through the countries of the North African coast and the middle east into India, followed by several southeast Asian countries, China, Taiwan, and Korea before reaching Japan.
No matter which way it goes, it's quite a trip, isn't it?
If you're interested,
here's a neat transit style map of the internet connections between countries.