[robotmay]

Ah yes you're right - looks like that can be handled with CSS: https://www.w3.org/International/articles/vertical-text/. Although from what I've seen most Japanese websites tend to be left-to-right instead anyway.

Hebrew would be a more valid second example I think. I'd be curious to know how many languages maintain their RTL preference online.

[dhosek]

Japanese¹ isn't a right to left language, exactly. It can be written horizontally, in which case it's L-R, top to bottom, or, vertically, in which case it's top to bottom, with columns running R-L, but functionally, this is still like L-R typesetting, just with the characters rotated 90° CCW and the pages are then read in the same order as pages in a R-L book. This is typical of manga which is why there might have been confusion by the OP about the directionality of Japanese.

⸻⸻⸻

1. All of this also applies to Chinese and Korean. Interestingly, traditional Mongolian script is also written vertically, but in columns left to right rather than right to left.