QLoRA fine-tune of llm-jp/llm-jp-4-8b-instruct, distilled from Claude Sonnet 4.6 on 3,189 filtered Japanese elementary-school math (中学受験 算数) training examples with step-by-step solutions. Target audience: 5–6年生 preparing for 中学校 entrance exams.
This model is best understood as a style/format distillation artifact. It tends to produce concise, numbered 算数-style explanations (つるかめ算、面積図、線分図, etc.) rather than the algebraic / LaTeX-heavy responses that the base model often defaults to.
Research artifact, not a general-purpose AI service. This is a narrow-domain student model produced via knowledge distillation from Claude Sonnet 4.6 for non-competing research and educational use, consistent with Anthropic's Commercial Terms §D.4. It is not a substitute for Claude/GPT-style general assistants. See Intended use and Out of scope below before deploying.
Correctness warning: do not use this model as an answer oracle. A follow-up audit found multiple wrong final answers in both the Sonnet-generated teacher/reference data and this student model's outputs. The supported claim is improved explanation style/readability, not verified answer accuracy.
Overview
This model is a QLoRA fine-tune of llm-jp/llm-jp-4-8b-instruct, distilled from Claude Sonnet 4.6 on 3,189 filtered step-by-step solutions to Japanese elementary-school math problems used in 中学受験 (private middle-school entrance exams). The raw training split contained 3,213 examples; 24 extremely short records were filtered before training. Target audience: 5th–6th-grade serious learners.
This should be treated as a style and formatting distillation model, not an answer-verification model. It tends to produce concise, numbered explanations using elementary-school arithmetic methods (つるかめ算 / "crane-and-turtle" method, 差集め算 / "difference-gathering" method, area-diagrams, ratios, etc.) rather than algebraic equations with variables, which fall outside the Japanese elementary curriculum.
Intended use (research & education)
Generating step-by-step explanations for elementary-school math problems
Creating practice / teaching material for 中学受験 students
Tutoring support where explanations must stay within the elementary curriculum
Academic and practical research into Japanese-language SLM distillation
Out of scope
Use as a general-purpose AI assistant / chatbot (this is a narrow-domain artifact)
Automated answer checking or final-answer generation without independent verification
Unsupervised educational content shown directly to children
Middle/high-school math (equations, functions, trigonometry)
Non-math Japanese tasks (reading comprehension, science, social studies)
General Japanese chat (not evaluated)
Use as the foundation of a product or service that competes with Claude, GPT-style assistants, or other general-purpose AI offerings
Commercial use note
This model is released under Apache 2.0, but part of the training corpus was generated by Claude Sonnet 4.6, and use of those outputs is subject to Anthropic's Commercial Terms §D.4 (restrictions on building competing AI products). Anyone considering commercial deployment should review Anthropic's current terms independently.
Limitations and known issues
Correctness is out of scope for this release. Always check the final answer against an official or human-verified source. Soonet 4.6 produced answers are not always correct based on the spot checks.
Distillation ceiling: this model is bounded by Claude Sonnet 4.6's elementary-math capability. If Sonnet makes a mistake, the student model can inherit it.
The training "solutions" were generated by Sonnet, not authored by human 塾 teachers. Phrasing may diverge from published model-answer guides.
Not evaluated on non-math tasks. Performance on reading comprehension, science, social studies, or general chat is unknown.
Released under Apache 2.0. Please also review the license of the base model (llm-jp/llm-jp-4-8b-instruct).
Citation
@misc{nakazato2026sansu,
title = {llm-jp-4-8b-instruct-sansu: A distilled SLM for Japanese elementary math instruction},
author = {Yuki Nakazato},
year = {2026},
url = {https://huggingface.co/ynakazat11/llm-jp-4-8b-instruct-sansu},
note = {QLoRA distillation from Claude Sonnet 4.6 on Japanese 中学受験 math problems.},
}