[_hzw]

KOReader doesn’t support Japanese vertical rtl layout without a hack (e.g., rotating the fonts) is the single reason I don’t use it. The stock software on Kindle, on the other hand, does care about this a lot and its implementation is very good. In the end, I just built my own local server and a KUAL app to sync books and notes and progress in/out from jailbroken devices.

[leecming]

there's a fork that adds proper tategaki support - https://github.com/m-tky/koreader-tategumi

and with the plugin system allows you to use the built-in Japanese dictionary a la Yomitan with one-tap lookups

[_hzw]

Thanks!