Because it's hard to remember how to handwrite complex kanji (many people have character amnesia in real life due to smartphone usage), I casually wondered if it was possible create a Japanese orthography that was: (1) easily scannable (which rules out hiragana); (2) disambiguated words without Kanji; (3) still relatively compact? (which hiragana is not).
I figured a good substrate to start from was romaji + a new emoji system.
You know how people think LLMs can't invent things? o3 just invented this system whose goal is to maximally disambiguates homophonic Japanese words (performing the same semantic compression role that Kanji does today). This is the first iteration. After each romaji noun, it tags it with a geometric shape. These are the 30 tags o3 came up with (based on homophones requiring disambiguation):
| Diacritic | ◐ living | ▢ built / object | ⬢ nature | ◊ abstract | ⟐ action / event |
| ------------- | ---------------------- | ---------------------- | ----------------------- | ---------------------------- | --------------------------- |
| • top dot | ◐• adult / main person | ▢• building / place | ⬢• plant / flora | ◊• idea / thought | ⟐• movement / travel |
| – bottom bar | ◐– child / minor | ▢– tool / instrument | ⬢– water / liquid | ◊– emotion / feeling | ⟐– communication / speech |
| + right plus | ◐+ group / collective | ▢+ vehicle / transport | ⬢+ weather / sky | ◊+ social tie / relationship | ⟐+ creation / production |
| × left cross | ×◐ animal (non-human) | ×▢ food / consumable | ×⬢ mineral / material | ×◊ value / moral | ×⟐ perception / sense |
| | center bar | ◐| deity / honorific | ▢| document / media | ⬢| terrain / landscape | ◊| state / condition | ⟐| change / transformation |
| ‿ bottom arc | ◐‿ anatomy / body part | ▢‿ container / vessel | ⬢‿ energy / fire | ◊‿ knowledge / data | ⟐‿ rest / passive state |
現代における日本語の一般的な表記法は漢字仮名交じり文であり、漢字と平仮名（昔の法令などでは片仮名）を交えて表記する。漢字は実質的な意味を表す語に使われ、平仮名は主に活用語尾[注 1]や助詞に使われる。朝鮮語などでは漢字が主として字音語にしか使われないのに対し、日本語では和語にも使われ、外来語を除いてほとんどの語に使うことができる。煙草（タバコ）や合羽（カッパ）、珈琲（コーヒー）など大航海時代以降にヨーロッパから入った語彙には、外来語であるにもかかわらず漢字が使われるものがある。
gendai◊| ni okeru nihongo◊‿ no ippan-teki na hyōkihō◊‿ wa kanji▢| kana▢| majiri bun▢| de ari, kanji▢| to hiragana▢| (mukashi no hōrei▢| nado de wa katakana▢|) o majete hyōki◊‿ suru. kanji▢| wa jisshitsu-teki na imi◊• o arawasu go◊‿ ni tsukaware, hiragana▢| wa omo ni katsuyō-gobi◊‿ ya joshi◊‿ ni tsukawareru. chōsengo◊‿ nado de wa kanji▢| ga shutoshite ji-on go◊‿ ni shika tsukawarenai no ni taishi, nihongo◊‿ de wa wago◊‿ ni mo tsukaware, gairaigo◊‿ o nozoite hotondo no go◊‿ ni tsukau koto◊‿ ga dekiru. tabako⬢• (tabako) ya kappa▢– (kappa), kōhī×▢ (kōhī) nado dai-kōkai-jidai◊| ikō ni Yōroppa⬢| kara haitta goi◊‿ ni wa, gairaigo◊‿ de aru ni mo kakawarazu kanji▢| ga tsukawareru mono◊‿ ga aru.
(of course, it's incorrect in parts... because LLM)
But the idea has legs. It will probably not replace Kanji due to cultural inertia, but this could a kind of shorthand especially for handwriting.
I'm pretty impressed! o3 just invented something new. It combined romaji and a tag system that it hallucinated to design a new Japanese orthography. As far as I can tell (I could be wrong), something of this nature has not been done before.