Vanguard Lawyers Tokyo scales AI across the firm with Microsoft 365 Copilot

Vanguard Lawyers Tokyo has built a strong reputation advising global companies on labor disputes, litigation, and crisis management. But the nature of legal work was shifting around it. Clients were arriving with new kinds of requests, asking firms to audit years of legal records with AI or verify AI-generated answers to legal questions. AI-forward competitors were completing in two days what once took a week.

The firm identified three areas where it needed to move fast: transcribing meeting notes was consuming staff time; translation from Japanese to English was slow and unreliable; and locating past cases required institutional knowledge that not everyone had.

Vanguard Lawyers Tokyo concluded that firms failing to adapt quickly to AI would struggle to survive, and it was determined to lead rather than follow.

Prioritizing security and Microsoft integration

Vanguard Lawyers Tokyo piloted Microsoft 365 Copilot in early 2025, giving lawyers, support staff, and IT representatives two weeks to use it in their daily work. The results were clear enough that the firm moved quickly to roll it out to every associate.

Two factors drove that decision. The first was the deep connection between Copilot and Microsoft SharePoint, giving staff access to the firm's entire library of historical documents, databases, and legal resources without switching platforms. The second was security. “We have faith in Microsoft's security, and since Copilot runs on the solid security foundation of Microsoft 365 E5, we thought Copilot would be safer from the perspective of information protection,” says Masahiko Kinoshita, Partner Attorney at Vanguard Lawyers Tokyo. For a law firm handling sensitive client data, that mattered greatly. A formally approved AI tool also eliminates the risk of information leakage from staff using unauthorized free alternatives.

“Our partners had a vision that AI would become an essential tool in the future, especially for the younger generation, and we expected that not only lawyers but also all staff would use AI to streamline their work,” says Maria Abe, Associate Foreign Law Attorney at Vanguard Lawyers Tokyo. “That’s why we secured licenses for everyone.” The firm has encouraged staff to explore Copilot across every application in the Microsoft 365 suite, building familiarity through daily use rather than one-off training sessions.

Changing how legal work gets done

A significant portion of a lawyer's day is spent reading and writing messages, often across languages. “The speed of email creation has increased significantly,” says Maya Sugimoto, Attorney at Vanguard Lawyers Tokyo, describing how Copilot changed that routine. “If you need to write an email in English, you can quickly outline what you want to say in Japanese and ask Copilot to translate it into English, all within Outlook, so you don't have to open a browser and go back and forth,” she adds.

Copilot also handles subtleties that standard translation tools miss. Abe notes that when composing Japanese emails, Copilot generates text that accounts for honorific expressions and cultural nuance, producing natural, sophisticated sentences that generic tools can’t match.

Beyond email, Copilot has changed how lawyers begin a new case. By summarizing documents, identifying key points, and pulling relevant information from SharePoint, it moves associates from intake to a working first draft far more quickly, freeing lawyers to focus on work that requires human judgment.

Brainstorming and research review have also changed. Associates can describe what they need in plain Japanese, and Copilot will generate options and help surface new angles. Abe uses the Research Tool in Copilot for in-depth contract analysis. “Copilot understands the background of who the parties are and what my purpose in the review is, and it uses that to consider solutions that are advantageous to the client,” she says. “It also identifies which parts of the law are likely to apply when referring to regulations, saving time and leading to improved accuracy and quality.”

The firm also set out to fix meeting transcription, one of the original pain points. Copilot generates summaries from recorded meetings, and in many cases the minutes—complete with to-do items—are delivered on the same day.

Measuring what Copilot delivers

The results at Vanguard Lawyers Tokyo have been swift and concrete: Associates who once spent about 10 minutes drafting a single English email now complete the same task in five, saving 25 hours a month per associate. Translation outsourcing has dropped sharply, with Copilot delivering sufficient quality, even for complex contracts. Jobs that previously took a week to finish are completed in two days, which is reshaping client expectations and increasing competitive pressure among firms.

Sugimoto sees the change in personal terms. “For me, it is like a work partner. Copilot allows me to focus on the work that only I can do. I'm also more satisfied with my job,” she explains.

For a firm that committed early to the use of AI, the competitive advantage is already being felt in the speed, quality, and cost of its work. “In the future, AI will become a must-have tool for everyone,” Kinoshita concludes. “AI can make a big difference in the speed and quality of work. Copilot can be everyone's business partner.”

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