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Main Authors: Fujita, Shogo, Naraki, Yuji, Zhu, Yiqing, Mori, Shinsuke
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2512.11297
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author Fujita, Shogo
Naraki, Yuji
Zhu, Yiqing
Mori, Shinsuke
author_facet Fujita, Shogo
Naraki, Yuji
Zhu, Yiqing
Mori, Shinsuke
contents This paper introduces LegalRikai: Open Benchmark, a new benchmark comprising four complex tasks that emulate Japanese corporate legal practices. The benchmark was created by legal professionals under the supervision of an attorney. This benchmark has 100 samples that require long-form, structured outputs, and we evaluated them against multiple practical criteria. We conducted both human and automated evaluations using leading LLMs, including GPT-5, Gemini 2.5 Pro, and Claude Opus 4.1. Our human evaluation revealed that abstract instructions prompted unnecessary modifications, highlighting model weaknesses in document-level editing that were missed by conventional short-text tasks. Furthermore, our analysis reveals that automated evaluation aligns well with human judgment on criteria with clear linguistic grounding, and assessing structural consistency remains a challenge. The result demonstrates the utility of automated evaluation as a screening tool when expert availability is limited. We propose a dataset evaluation framework to promote more practice-oriented research in the legal domain.
format Preprint
id arxiv_https___arxiv_org_abs_2512_11297
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle LegalRikai: Open Benchmark -- Benchmark for Complex Japanese Corporate Legal Tasks
Fujita, Shogo
Naraki, Yuji
Zhu, Yiqing
Mori, Shinsuke
Computation and Language
This paper introduces LegalRikai: Open Benchmark, a new benchmark comprising four complex tasks that emulate Japanese corporate legal practices. The benchmark was created by legal professionals under the supervision of an attorney. This benchmark has 100 samples that require long-form, structured outputs, and we evaluated them against multiple practical criteria. We conducted both human and automated evaluations using leading LLMs, including GPT-5, Gemini 2.5 Pro, and Claude Opus 4.1. Our human evaluation revealed that abstract instructions prompted unnecessary modifications, highlighting model weaknesses in document-level editing that were missed by conventional short-text tasks. Furthermore, our analysis reveals that automated evaluation aligns well with human judgment on criteria with clear linguistic grounding, and assessing structural consistency remains a challenge. The result demonstrates the utility of automated evaluation as a screening tool when expert availability is limited. We propose a dataset evaluation framework to promote more practice-oriented research in the legal domain.
title LegalRikai: Open Benchmark -- Benchmark for Complex Japanese Corporate Legal Tasks
topic Computation and Language
url https://arxiv.org/abs/2512.11297