Definitely not limited to one country - they are basically one of the largest video game companies in the world with majority holdings in Riot Games, Supercell, Epic Games and a large percentage of Activision Blizzard.
http://www.businessinsider.com/running-list-softbank-investm...
Biggest deal is Softbank owns ARM, granted that is a UK firm but ARM really is the future especially now that Windows 10 can run on ARM. https://www.bloomberg.com/news/articles/2017-08-07/arm-bulks...