Bengo4.com, Upgrades "Legal Brain Agent" to Japan's First* Unified Legal AI Agent

 Bengo4.com, Inc. (Minato-ku, Tokyo; Representative Director, President and CEO, Lawyer: Taichiro Motoe; hereinafter the “Company") will upgrade its AI agent for an in-house legal department and lawyers, "Legal Brain Agent", and begin offering the new version on June 29, 2026.
  The service has evolved into Japan's first* "Unified Legal AI Agent" that integrates highly reliable legal data such as Japanese laws, judicial precedents, guidelines, and specialized legal books into its own database, allowing users to proceed with legal tasks from issue examination to research, analysis, and drafting of emails and documents through repeated dialogue.
  *As a legal-specialized AI agent that integrates major Japanese legal data (laws, judicial precedents, guidelines, and specialized legal books) in-house and operates as an agentic AI (autonomous execution type). (As of June 2026, based on Company research)



■ Development Background: An AI agent that fundamentally transforms how legal professionals work 
  The demands placed on corporate legal teams are expanding exponentially each year, driven by tighter governance requirements, frequent regulatory changes, ESG and sustainability mandates, and the growing complexity of international transactions. According to a survey*1 by Professional Tech Lab, a research organization operated by the Company, approximately 80% of In-house legal professionals in Japan are experiencing a surge in legal inquiries, turning departmental bandwidth constraints into a systemic structural challenge.
  Historically, keeping pace with this growing caseload has required legal professionals and lawyers to expend significant time and energy on manual workflows—from exhaustive literature research to document drafting and stakeholder reporting. To address these bottlenecks, the newly upgraded "Legal Brain Agent" is designed to revolutionize the traditional legal workflow.
  By autonomously identifying relevant sources, conducting deep research and analysis, and generating highly practical document drafts end-to-end, the AI handles the heavy lifting. This empowers users to dedicate their time to high-value, expert decision-making. Through human-AI collaboration and continuous dialogue, we are bringing a completely new style of working to the legal professionals.
*1: Professional Tech Lab, "Survey on Legal Talent Shortages and Trends in Legal Consultations" (Conducted June 2026, n=500)
 

■ Three Key Features of the Upgraded Legal Brain Agent
  The upgraded "Legal Brain Agent" is designed not merely as a research tool, but as a collaborative partner that addresses practical challenges and drives tasks forward alongside the user. Through dialogue, it provides robust support—from accelerating initial responses, even in unfamiliar areas, to generating practical, ready-to-use outputs. 

1. Comprehensive Agent Support: From Organizing Inquiries to Research and Document Drafting
  The most significant feature of this upgrade is its evolution into a unified legal AI agent capable of handling a broad spectrum of tasks, including organizing legal inquiries, serving as a discussion partner, conducting research, and drafting documents. It now assists with legal operations by understanding the conversational context and accurately identifying legal issues and potential risks. Furthermore, because it retains the memory of past conversations, users can repeatedly delve deeper into topics through ongoing dialogue until they are fully satisfied with the outcome. 

2. Highly Accurate Answers Powered by the Proprietary Legal Information Infrastructure "Legal Graph" 
  Responses are generated based on "Legal Graph," a proprietary legal information infrastructure that maps the relationships between Japanese laws, judicial precedents, guidelines, and specialized legal books.
. By relying on this internally developed data infrastructure rather than external data sources, we can maximize the AI agent's performance and achieve exceptionally high accuracy. Furthermore, all answers explicitly cite the primary sources they are based on, allowing users to apply them to their practical work with confidence. 

3. Continuous Quality Improvement by a Dedicated Team of Lawyers
  We have established a dedicated in-house team of lawyers focused entirely on product evaluation and quality verification. By identifying quality issues such as "misinterpretation of user intent" or "inaccurate information," and combining this human review with automated AI verification, the team continuously operates a cycle of root cause analysis, correction, and testing. 

< Feedback from Early Adopters >
"Research results that previously took three hours to gather were retrieved instantly with the Legal Brain Agent. Research tasks on par with our standard operations can now be completed in a fraction of the time." (Law Firm)
"The time required for document drafting, which used to take about four hours, has been reduced to less than a third." (Law Firm)
"Even for urgent consultations, we are now able to swiftly organize and present legal issues and response strategies." (In-house Legal Departments)
"We were initially concerned about the hallucinations common in general-purpose AI. However, after confirming that the Legal Brain Agent consistently provides evidence-based answers, we are now able to utilize AI in our daily work with complete confidence." (In-house Legal Departments)

■ Selected Use Cases for Legal Brain Agent


■ Comments from Early Adopters 
Wataru Tanaka, Professor of Corporate Law Institute of Social Science, The University of Tokyo
"I used the Legal Brain Agent when writing papers and communicating with researchers from other fields as well as lawyers. It introduced me to papers I was unaware of, allowing me to access previously unknown information and leading to new discoveries. In terms of efficiency, my impression is that research time is reduced to one-tenth in fields outside my expertise, and by about half in my specialized field. Going forward, I believe a clear gap will emerge in the field of legal research between those who can master AI and those who cannot. I highly recommend this tool to my fellow researchers." 

Wataru Shimizu, Attorney at Law, Anderson Mori & Tomotsune
"The new Legal Brain Agent is a truly unified legal AI agent. I had the opportunity to use it prior to release, and once you start using it, it quickly becomes indispensable. The peace of mind that comes from having original sources and evidence reliably displayed, coupled with the immersive experience of deepening one's thoughts through follow-up questions—both provide an outstanding experience not found in previous tools. Furthermore, the seamless screen transitions ensure that your concentration is never broken. A tool that is useful in every aspect of legal work has finally arrived. True innovation in legal operations begins here." 

Genichi Kataoka, General Manager, Head of Legal Department, Group Internal Control Division, KADOKAWA CORPORATION
"I initially started using it thinking it was a book search service, but I quickly realized it is something completely different. Even if you do not have a specific question in mind, simply inputting rough ideas or topics that caught your attention during work allows the Legal Brain Agent to extract insights from vast amounts of information through dialogue. It adjusts the clarity of its explanations to match the user's level of understanding, fostering a sense of trust much like a reliable partner. I feel that full-scale collaboration and task-sharing with AI are finally possible. I look forward to its continued evolution exceeding our expectations."

■ Comment from Yuji Inagaki, Head of Product, Legal Brain Business Division, Bengo4.com, Inc.
"While the utilization of generative AI is becoming a critical theme in the legal field, general-purpose AI lacks specialized legal knowledge. As a result, the risk of hallucinations could not be fully eliminated, posing challenges for professionals trying to use it confidently in practice. The Legal Brain Agent has achieved unprecedented accuracy in its responses by integrating a vast amount of legal data onto the same infrastructure as the AI agent itself. Moving forward, we aim to continue contributing to the improvement of our customers' productivity by providing an AI designed to support legal professionals." 

■ About Legal Brain Agent

   Legal Brain Agent is a unified legal AI agent designed for lawyers and in-house legal professionals, powered by Legal Brain, a proprietary legal AI technology infrastructure developed by Bengo4.com. Its fundamental differentiator from general-purpose AI lies in its design philosophy: it bases its responses solely on highly reliable sources—such as Japanese laws, regulations, precedents, guidelines and specialized legal books, and articles from "BUSINESS LAWYERS"—and ensures that every answer is accompanied by citations and references to the original sources.
Service Website: https://legalbrain.com/