I usually need to use a vpn to get Sky Sports abroad. I get it through a NowTV subscription, not sure if that makes a difference. Even then it sometimes recognises the vpn and kicks me out. It worked fine last Thursday, hopefully same again today.
Sky itself is only available in the UK. Their match coverage is generally sold on worldwide. For example in the Middle East I got games that Sky would broadcast through Bein Sports. Haven't a clue what the situation is in Japan though.