Thanks for pointing that out. He just didn't make himself very clear on what plays what, he's not really saying the White PCE plays all hucards.
>The white PC-Engine plays the japanese and the TG16 american cards.
Here he just means the PCE plays Jap games and the TG16 plays US games, he just left out "plays" after TG16 making it sound like the PCE plays both.
>The TG16 can be upgraded with an adaptor to play also japanese cards. For the japanese white engine there's no such convertor, so you won't be able to play american games.
Notice the 2nd sentence, it says you can't use a convertor on Jap systems so you can't play any US hu's on them.
Only the US systems were capable of using convertors.