Lawyers vs Python
When the Floor Drops
I'm a Brazilian living in Japan. Married to a Japanese, with a daughter.
Now I'm getting divorced.
When you're a foreigner divorcing in Japan, the power imbalance is brutal:
- The law is dense legalese - in Japanese, of course.
- Your spouse already has a lawyer lined up and a game plan.
It feels like being a kid thrown into a ring with Mike Tyson.
- You're told: "Just sign here.
"And you don't even know what you're giving up.
My biggest fear: losing my daughter, with no say in visitation.
Searching for Answers
I googled. I ChatGPT'ed: "divorce custody Japan."
Some info popped up, but nothing that really prepared me.
So I tried a lawyer consultation (¥10,000/hour).
The lawyer was polite, answered my questions.
But the vibe was: "You're not even officially divorcing yet. Don't bother me until you have something legally sound."
I tried another lawyer. Conflicting answers. WTF?
I started realizing: lawyers are just humans who read those docs, interpret them, and charge per hour to repeat them back (sometimes unreliably).
Lawyers vs Python
George Hotz once said: "A human brain is ~20 PFLOPS."
So yeah, lawyers can be powerful. But also expensive, inconsistent, and slow.
Meanwhile, I've got a Linux box sitting under my desk:
- AMD Ryzen 5 4500 (6 cores / 12 threads)
- NVIDIA RTX 3060 (12GB)
- 16GB RAM
I was already running LLMs locally. So I did the obvious thing: I built an app.
What Broke First
I thought this would be a simple FastAPI RAG endpoint. It wasn't.
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Data chaos: vertical Japanese PDFs, scanned tables, XML statutes with kanji article numbers (“第八百十九条”).
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Tokenization hell: standard English NLP breaks on CJK. I had to build Japanese-aware BM25 retrieval + embeddings.
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Hallucinations: vanilla LLMs love to make up laws. That’s unacceptable in custody disputes. So I set guardrails:
Quote statutes verbatim or say “⚠️ no excerpt found.”
Don’t invent child-support numbers.
The Build
I ended up building a local RAG app:
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Corpus: Japanese Civil Code (JP/EN), Domestic Relations Procedure Act, Hague Act, Houterasu/Embassy guides, 2019 child-support tables.
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Retrieval: hybrid ranker (BM25 + embeddings), routed by issue (custody, visitation, child support, procedure).
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Guardrails:
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Custody → always cite Civil Code 819 & 766
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Visitation → guides + phased schedules, only if retrieved
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Child support → cite 算定表, never fabricate
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I also fed a case profile - just a simple YAML file with facts about my situation - so the model always had my context
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Not Walking Blind
Divorce is hell. Especially with kids.
I wish these things could always be solved amicably. Without lawyers. Without fear.
But they aren’t. At least not yet.
What I built doesn’t solve everything. But it means I’m not walking blind anymore.