“Legal Brain,” an AI Agent Specializing in Legal Affairs, Surpasses Human Beings Achieves Correct Answer Rate of 96.5% in the 2025 Bar Exam (Multiple Choice Section)

Bengo4.com, Inc. (Minato-ku, Tokyo; Taichiro Motoe, Representative Director, President and CEO, Lawyer; hereinafter the “Company”) announces that Legal Brain, an AI platform specializing in the law, scored 169 out of 175 points (correct answer rate: 96.5%) in the bar exam (multiple choice section) held in 2025, topping the highest score among human examinees of 167 points. The average score for this year’s bar exam was about ten points lower than last year’s, showing that the exam is becoming more difficult. Despite this, the AI demonstrated its highest-ever level of accuracy.

■ Technical background: One of the largest legal databases in Japan and proprietary search technology

The outcome is supported by two technological advantages possessed by Legal Brain.

One is its legal database, one of the largest of the kind in Japan. Legal Brain has a unique database encompassing basic legal data such as laws, precedents and guidelines and credible specialized data that does not exist on the Web, including about 2,400 specialized books obtained through a partnership with about 50 publishers and about 300,000 precedents written in Hanreihisho. Obtaining knowledge from the high-quality offline data that general-purpose AI cannot learn ensures accuracy and comprehensiveness of the data. It is also compatible with questions demanding highly specialized knowledge such as those of a bar exam.

The second advantage is its high accuracy in data retrieval. The core of Legal Brain lies in its ability to correctly understand the intent of questions and properly select the right books and relevant text in the books from among an enormous amount of data. This is attributable to Legal Graph, the original knowledge graph that links relationships among different data (e.g. citation, reference) through natural language processing. This technology achieves very accurate search with an understanding of context, something that is beyond mere keyword search.

■ Overview of a bar exam (multiple-choice section)

Questions in the bar exam’s multiple-choice section in 2025 consisted of three subjects including the constitution, civic law and criminal law. The maximum possible score is 175 points. To advance to an essay-type exam, you have to earn 81 points or higher. The average score among examinees was 102 points and the highest score was 167 points.

■ Demonstration results of different general-purpose AI models

We let each of the different general-purpose AI models answer the questions three times. Average scores are shown below.

■ Accuracy that clearly states the source

Legal Brain not only achieved a high correct answer rate of 96.5%, in all of its answers it also correctly selected the source literature, such as laws, precedents, books, and guidelines. In contrast, general-purpose AI can generate correct answers, but users cannot check the sources being used for the answers. “Accuracy that can clearly state its source” is the core of credibility in legal work. In that regard, Legal Brain has an overwhelming advantage over general-purpose AI.

■ Future outlook

Based on the high accuracy demonstrated in the bar exam, Legal Brain facilitates further improvements in speed and accuracy and expands content such as legal books and precedent data. This is designed to more speedily and accurately support all processes of search, analysis and judgment in legal practices and to overwhelmingly enhance its convenience for users. We will strive for the democratization of laws, namely a society where everyone can access credible legal knowledge, through the continued evolution of AI technologies.

■ About Legal Brain, a law-specific AI platform

Legal Brain is an AI platform designed for the comprehensive study of legal data, including laws, regulations, precedents, guidelines and specialized books. Its advanced language capabilities have been specialized for the Japanese-language legal context. Legal Brain enables users to process an enormous amount of legal data and access the most relevant information faster than anything else.