Note that GP is incorrect that you need lowercase to express URLs and qrcode has an "alphanumeric" mode (based around uppercases which works fine), but even then qrcode's alphanumeric mode is slightly less efficient as it needs 5.5 bits per character versus 5 for Aztec.
Kanji has its own qrcode encoding mode (the qrcode encoding modes are numeric, alphanumeric[0], byte, kanji, structured append[1], ECI[2] and Code128[3]).
[0] digits, uppercase ascii letters and 9 symbols
[1] to split messages across multiple codes
[2] additional "local" encodings: https://strokescribe.com/en/ECI.html
What I do like about HN is the comments. Someone here usually knows what they are talking about and can explain it well.
Thanks!
I'd ask why they didn't just improve QR codes, instead of making yet another format, but I'm not sure I want to know the answer(s).
Thanks!
I am pretty grateful I'm not tasked with implementing these.