MNTSQ

Notes compiled from publicly available sources. Last updated: 2026-10-11. Every figure is linked to the source it came from and dated. Verify against primary sources before relying on them.

TL;DR

MNTSQ (MNTSQ株式会社, read モンテスキュー; English name MNTSQ, Ltd.) is a Tokyo company established on 2018-11-14. Its founder and CEO, Ryuhei Itaya (板谷 隆平), is a lawyer at the law firm Nagashima Ohno & Tsunematsu (長島・大野・常松法律事務所, "NO&T"); the company names AI engineer Takahiro Anno (安野 貴博) and Yotaro Katayama (堅山 耀太郎) as co-founders. It sells MNTSQ CLM, a contract lifecycle management system for large enterprises: legal-matter intake and contract review (案件管理), a contract ledger (契約管理), a clause-level contract database, and LLM-based features sold as MNTSQ AI契約アシスタント and MNTSQ AI Agent. NO&T invested ¥800M (8億円) in 2019 and supervises the templates and playbooks shipped in the product. Two more large law firms, Nishimura & Asahi (2024) and Mori Hamada & Matsumoto (2025), later took stakes as well.

• Scale as stated by the company: used by 41 of Japan's top 100 companies by revenue (2026-05-12), and by 42 as of 2026-06-12 (2026-06-29). The company also reports more than 2,000 adopting companies, counting group companies, as of 2026-05 (2026-07-07).
• Funding: the company has not published a cumulative total. Disclosed rounds are ¥800M from NO&T (2019-10-21), a ¥1.0B シリーズB from ALL STAR SAAS FUND (2023-09-19), and about ¥1.0B in 2024 from three corporate VCs plus a bond and a loan (2024-06-03). Nishimura & Asahi and Mori Hamada & Matsumoto invested undisclosed amounts.
• Team: 120 employees as of 2026-07-31. The development division (開発本部) has about 50 people in four teams as of 2026-08 (Software Engineer (Backend) posting; accessed 2026-10-11).
• Engineering: a Ruby on Rails core (Ruby since founding), Python services (FastAPI, Celery) and a Vue.js/TypeScript frontend. Infrastructure is AWS (ECS/Fargate, Aurora MySQL, SQS, OpenSearch), with Google Cloud (Vertex AI, Cloud Vision API) called from AWS workloads (postings, tech blog, 2026-09-29). All postings reviewed are in Japanese and do not state an English requirement. Engineers work hybrid, with at least 5 office days per month.

Basic

Programs and awards. The company was selected in Nikkei's "NEXTユニコーン調査2024" (notice, 2025-01-17). It was adopted into the "かんぽ生命 - アフラック - 日本郵便 Acceleration Program 2025" (2025-08-15). MNTSQ CLM received ITreview Grid Award "Leader" ratings, the fourth consecutive one for 2026 Summer (2026-07-15). The company won the 最優秀賞 in the 「はたらくを楽しく」 category of HR's SDGsアワード2026 and was also named 準グランプリ (2026-06-29).

Law-firm relationships as described by the company

• NO&T. The company says it was "創業当初から長島・大野・常松法律事務所の全面的なサポートを受けて2018年11月に設立" (2025-10-09). It ran a private pilot of its NLP software inside NO&T from 2019-02, and the product was used in NO&T's legal due diligence work. On 2019-10-21 it announced a capital and business alliance with NO&T and PKSHA Technology, including ¥800M from NO&T (2019-10-21). Two NO&T partners joined the board as outside officers (2019-11-13). NO&T supervises the contract templates ("MNTSQ雛型") and the playbook (審査基準集) supplied as standard with MNTSQ AI契約アシスタント (2026-01-16, AI契約アシスタント page). The two co-published the book "LegalTech" (2020-12-07).
• Nishimura & Asahi (西村あさひ). A strategic collaboration that includes an investment in MNTSQ; the firm also began using MNTSQ CLM (2024-06-04).
• Mori Hamada & Matsumoto (森・濱田松本). A capital and business alliance that includes an investment. The parties will consider offering Mori Hamada legal content on MNTSQ's platform, combined with MNTSQ's AI, and will consider Mori Hamada using MNTSQ technology (2025-05-07).
• The company summarises this as three of Japan's four largest law firms (四大法律事務所) participating in its business (2026-05-22).

Market and regulatory context as stated by the company

• When it launched MNTSQ for Enterprise in 2020, the company cited remote work during COVID-19. It also cited new questions about consolidating e-signed contracts across multiple services and complying with the 電子帳簿保存法 (Electronic Books Maintenance Act) (2020-12-07).
• In the Series B release, the CEO wrote that LLM progress, together with the fact that "弁護士法に関する社会的検討に一定の目処がついた", led the company to plan delivering AI contract review directly to more customers (2023-09-19).
• Current engineering postings describe the contract domain as late to digitalise, with large companies running their own on-premise systems. They also state that the number of bar-exam candidates is about half of what it was ten years ago (posting; accessed 2026-10-11).

Product

Product line-up and feature areas

The site groups the product into five modules (product index, homepage; accessed 2026-10-11):

Other surfaces listed on the homepage:

• AI contract review as a Word plug-in. It compares a counterparty draft with the customer's template and surfaces similar past contracts. It was released 2024-04-01 (2024-02-28). On 2026-09-07 MNTSQ AI Agent was added inside Word, where it:
• proposes a review policy before review starts;
• writes tracked-change redlines and comments;
• checks the customer's own playbook first and falls back to the law-firm-supervised playbook;
• flags formal defects such as inconsistent clause numbering and leftover placeholders (2026-09-07).
• Templates. "MNTSQ雛型" are NO&T-supervised templates with commentary. The range was doubled on 2026-01-16, and 13 templates, including AI-service terms of use, were added on 2026-06-18.
• Languages and currencies.
• English UI: 2023-10-02.
• All ISO 4217 currencies in contract management: 2025-12-16.
• AI analysis (element decomposition) of contracts in languages beyond Japanese and English, such as Chinese, Thai and German: 2026-01-21.
• Security features. Data on AWS is stored encrypted, and SSO and IP-address restriction are included at no extra charge (homepage; accessed 2026-10-11).

Integrations and API

• E-signature. DocuSign and CloudSign signed-contract import has been available since 2021 (CloudSign, 2021-04-14). It was extended on 2026-07-23 to cover the whole signing flow: creating e-signature drafts from a matter, tracking sending history, and automatically registering signed documents to a ledger (2026-07-23).
• Chat. Slack integration covers comment notifications, threaded replies written back to the matter timeline, and matter creation (2026-08-06). Microsoft Teams covers notifications and replies, including from the mobile app (2026-09-01).
• Email and storage.
• Email correspondence is ingested into the database, with full-text search of attachments.
• Files are imported from SharePoint, Google Drive and Box.
• User and permission changes can be applied by importing a settings file (homepage; accessed 2026-10-11).
• Public API. The 「案件管理公開API」 provides file upload and download, retrieval of matter details, and creation and update of matters (2026-04-07). Date and time fields were standardised to ISO 8601 with time zone on 2026-06-16. No public API reference was found.
• Counterparty master. Counterparty records can be created from the National Tax Agency corporate master. Name changes are reflected automatically, and old names are kept as aliases (2026-05-19).

Commercialization

Pricing is an initial fee (initial setup and implementation support) plus a monthly fee (service use and support), quoted according to the customer's issues and scale. No public price list was found; a plan guide is offered as a download behind a form (homepage; accessed 2026-10-11). Each customer is assigned a consultant from implementation onward, including support for migrating existing data, and the company runs user conferences ("MNTSQ Meeting"). Engineering postings describe the business as "受託ゼロ、個社カスタマイズゼロ" (no contract development, no per-customer customisation) (posting; accessed 2026-10-11).

Product history

Reported scale over time

Announced customers and partners

The clients page and the case study index list further users (accessed 2026-10-11). Announced users also include law firm 稲葉総合法律事務所 (2021-12-22).

Stated plans

• Series B use of funds: accelerated investment in product development, including LLM use, and delivery of AI contract review (2023-09-19).
• 2024 round: joint solution development with the investing companies would be considered within the capital and business alliances (2024-06-03).
• Stated aspiration for MNTSQ AI Agent: an agent that acts autonomously "契約交渉まで行ってくれる" (all the way to negotiating contracts) (2025-09-19 release on site, 2026-09-07).
• On the COO appointment: expand adoption and share in the Japanese enterprise segment, described as the hub of a future contract network and platform (2026-06-01).
• A current HR posting gives its background as "IPO準備に向けた体制強化" and states that organisational preparation toward an IPO is under way (制度企画・労務 posting, page metadata datePosted 2026-09-07; accessed 2026-10-11).

Founder

板谷 隆平 (Ryuhei Itaya) — Founder / CEO and 代表取締役. The about page still lists him as a lawyer at NO&T (about). Engineering postings state that he also serves as CPO (posting; accessed 2026-10-11).

• 2013: graduated from the University of Tokyo Faculty of Law, having passed the 司法試験予備試験 (preliminary bar examination) while a student (column, 2025-03-03).
• 2014: registered as a lawyer and joined NO&T, advising on M&A and on AI/IT technology matters. He founded MNTSQ while working at the firm (about).
• Director (理事) of 一般社団法人AIリーガルテック協会, as stated in a 2025-07-09 release.
• 2025-12: ranked 10th in the "人工知能（AI）ガバナンス" category of Nikkei's lawyer ranking (2025-12-24).
• 2026-05: received the "Legal Intrapreneur" award at the Financial Times "Asia-Pacific Innovative Lawyers Awards 2026" (2026-05-22).

安野 貴博 (Takahiro Anno) — a company column states that Itaya co-founded MNTSQ with Anno. It describes Anno as a natural-language-processing specialist who trained the first models on about 100 sample unfair clauses that Itaya wrote (column, 2025-03-03). A 2019 company post on Wantedly by Katayama describes Anno as also a director (取締役) of MNTSQ (Wantedly, 2019-10-29). He is not listed in the management section of the current about page.

堅山 耀太郎 (Yotaro Katayama) — listed as "Co-Founder / 取締役" and as CFO of Preferred Networks on the about page. His Preferred Networks biography gives this career (PFN leadership, JA; accessed 2026-10-11):

• 2016: master's degree from the University of Tokyo Graduate School of Engineering, then Goldman Sachs Japan.
• Co-founder and director of BEDORE (now PKSHA Workplace).
• 2018: joined MNTSQ's board as a co-founder, responsible for engineering and finance.
• 2023: doctorate in engineering from the University of Tokyo, earned while at MNTSQ.
• 2024-05: CFO of Preferred Networks.

Selected leadership

The company's organisation chart has four units under the CEO: 事業本部, 開発本部, 人事本部 and 経営管理部. 開発本部 contains three parts (Engineering Team Deck):

• 開発部: CLM application, CLM platform, legal-agent, business-division and enabling teams.
• プラットフォーム部: SRE and QA teams and a security office.
• リーガルエキスパートチーム: legal new-business planning and legal consultants.

Funding

• The 2019 release states PKSHA's investment had already been made before the NO&T round, without an amount (2019-10-21). A follow-up release describes the alliance as raising "約8億円" (2019-11-13).
• In the Series B release, the CEO states that in this round the company decided to accept investment from a new VC in order to keep making growth investments ("新規のVCによる出資を受け入れることといたしました") (2023-09-19). No release labelled シリーズA was found.
• The 2024 release states the round followed demand for MNTSQ AI契約レビュー, launched that April. Investor comments from MUFG's and JGC's investment arms state that MUFG Bank and the JGC group were already MNTSQ CLM users (2024-06-03). BRIDGE described the round only as "直近のラウンド" (BRIDGE, 2024-06-04).
• The Series B release was published the same day as the announcement that MNTSQ AI契約レビュー was in development (2023-09-19).

Engineering

Technology stack and platforms

Confirmed by the company's technical writing (tech blog and releases):

• Ruby / Ruby on Rails. The company states that Ruby has been the main language of its web service since founding in 2018 (2023-03-06). A 2026 post says the core of the service is Ruby on Rails (tech blog, 2026-05-11). The company was a Ruby Sponsor of RubyKaigi 2023.
• Asynchronous jobs. Rails background jobs moved from Resque on Redis to Amazon SQS, with priority-tiered and feature-specific queues and per-queue autoscaling (2026-05-11). Python workers use Celery on SQS (2026-06-29).
• Search. The service ran self-hosted Elasticsearch 7.x on EC2 until a no-downtime migration to Amazon OpenSearch Service, which ran from 2025-10 to 2026-06. The project consolidated per-tenant-group clusters into a single VPC domain with fine-grained access control, managed with Terraform (2026-08-26).
• AWS and Google Cloud. Applications run on Amazon ECS. Three backend services call Google Cloud's Vertex AI or Cloud Vision API, now authenticated through Workload Identity Federation instead of service-account keys. Deployment runs through GitHub Actions (2026-09-29).
• LLMs. A 2024 talk compared GPT-4o, Claude 3.5 Sonnet and Gemini 1.5 Pro for contract analysis. It weighed accuracy, context window, output speed, price and availability in a Japan region (the presenter's own assessment) (LT deck, 2024-07-11).
• Other tools. Other tech-blog posts cover Datadog, Redash, AWS Security Hub, Playwright and ECS Exec (archive; accessed 2026-10-11).

Listed in current job postings (hiring documents; Software Engineer (Backend), Tech Lead, and the same list in the Engineering Team Deck):

The postings state that development assumes AI tools such as Claude and Devin. Employees receive a Claude Enterprise account as a listed benefit (posting; accessed 2026-10-11).

Systems

The company runs a Japanese-language tech blog on Hatena Blog. Its sitemap lists 108 posts from 2020-11 to 2026-09, 24 of them in 2026 (tech.mntsq.co.jp; accessed 2026-10-11). The company also publishes on note and hosts events on connpass.

Technical background sought

From the current postings on HRMOS (accessed 2026-10-11):

• Software Engineer (Backend).
• Required: three or more years developing and operating web applications; independently solving technical problems; API and database design as a backend engineer.
• Preferred: Ruby on Rails, Vue.js or Python; leading BtoB system design through implementation; cloud infrastructure design and configuration management based on availability, security and fault tolerance (posting).
• Tech Lead.
• Required: five or more years of web-application design, development and operation; technology selection and architecture design; leading difficult projects as tech lead; BtoB system design.
• Preferred: product development with machine learning, NLP or search systems; search systems on Elasticsearch or Apache Solr; systems for highly specialised professional domains (posting).
• AI (NLP) Engineer.
• Required: systematic ML/NLP knowledge; three or more years building ML/NLP into products, designing evaluation metrics and improving performance; using major LLM APIs (OpenAI, Claude, Gemini); web-application or API development.
• Preferred: building AI agents with MCP or A2A; search systems on Elasticsearch or OpenSearch; data-platform work; LLM fine-tuning or pre-training; talks or papers at AI/NLP venues (posting).
• Lead Engineer (Frontend).
• Required: five or more years with Vue.js or React.
• Preferred: building and running a design system (posting).
• Design Engineer.
• Required: building, running and improving a design system (posting).
• Selection. The backend technical assignment is a schema-design exercise in which AI use is assumed. Final interviews are held in person, and the process includes reference and background checks (posting).

Industry domain

The work concerns Japanese corporate legal practice:

• contract drafting, review and negotiation between business units and legal departments;
• contract ledgers, renewal and deadline management;
• law-firm best practice in the form of templates and playbooks;
• e-signature and the 電子帳簿保存法 (Electronic Books Maintenance Act);
• the revised subcontracting law (取適法), for which templates were added (2026-06-18).

The development division includes a legal expert team of lawyers and former in-house legal staff who work on product planning (Engineering Team Deck). The CEO's recruiting message states "契約に詳しい必要はありません" (no need to be familiar with contracts) (careers site; accessed 2026-10-11). Engineering postings ask for interest in, and willingness to learn, the company's business domain rather than prior legal experience (posting).

Working conditions

Notes

Not publicly disclosed

Search scope for the findings below (2026-10-11):

• the official site and its sitemap: about, product, clients, case studies, news index and security policy;
• the careers site and every current posting on the HRMOS job board (23 roles), plus the HERP Career aggregator listing;
• MNTSQ's PR TIMES company page (104 releases listed);
• the tech blog sitemap, note, Speaker Deck (10 decks) and connpass;
• the GitHub organisation API, the NTA corporate number register, BRIDGE, and the PFN leadership page;
• Japanese and English web searches for MNTSQ, モンテスキュー and ＭＮＴＳＱ株式会社 combined with funding, ARR, 決算公告 and J-Startup.

TokyoDev returned HTTP 403 to automated access; Japan Dev has no MNTSQ company page (HTTP 404).

• Revenue, ARR, profitability and valuation. Not published. No 決算公告 was found in web search; the 官報 itself was not searched.
• Cumulative funding. The company has not published a total. The PKSHA, Nishimura & Asahi and Mori Hamada amounts are undisclosed, and no release labelled シリーズA was found.
• Engineering working language and visa policy. Not stated in any posting or careers page reviewed.
• Price list. Only the fee structure is public; a plan guide is gated behind a form.
• Public API documentation. The matter-management API is described in releases, but no public reference was found.
• Open source. The GitHub organisation MNTSQ was created 2018-11-21. Its metadata lists location "Japan" and no website, email or X account, and none of the company's sites reviewed link to it. It has four public repositories: three forks of Ruby/Rails tooling (apivore, ruby-ntlm, annotate_models) and one Python repository, simple-mcp-rag, last pushed 2025-10-21.
• Status page or SLA. None found.
• Turnover. Not published.

Inconsistencies across sources

• Founding year. The company's releases give 設立日 2018-11-14, and the NTA register shows the corporate number designated 2018-11-27 (NTA register). The company's own column with NO&T states "2019年にMNTSQを創業しました" (column, 2025-03-03).
• Top-100 customer count. The backend posting states 43 of the top 100 "2026年4月現在" (posting; accessed 2026-10-11). Releases published after that date give 41 (2026-05-12, 2026-05-22, 2026-06-01), and later 42 as of 2026-06-12 (2026-06-29).
• Katayama's board role. MNTSQ's about page lists him as "Co-Founder / 取締役" (about). Preferred Networks' biography says he "MNTSQの社外取締役も務める" (also serves as an outside director of MNTSQ) (PFN leadership).
• Development team structure. The postings describe 開発本部 as about 50 people in four teams (CLM, 法務エージェント, 事業部向け, イネーブリング), as of 2026-08 (posting). The 2026-09 deck splits CLM into application and platform teams and adds a separate プラットフォーム部 and a legal expert team (Engineering Team Deck). The sources do not state whether the 50-person figure includes the platform and legal expert teams.
• Release dates. Dates shown as 更新 on mntsq.co.jp news pages sometimes differ by a day from PR TIMES, for example 2019-10-20 versus 2019-10-21 and 2023-09-18 versus 2023-09-19. This page uses the PR TIMES dates.

Other

• The company's product names have changed over time:
• 2020: "MNTSQ for M&A" (law-firm due diligence) and "MNTSQ for Enterprise" (2020-12-07).
• 2022-01: the line-up is called "MNTSQ" (2022-01-26).
• From 2022-07: "MNTSQ CLM" (2022-07-19).
• 2026 releases describe it variously as 契約プラットフォーム and 契約AIインフラ (2026-08-06, 2026-09-01).
• The company's first large media campaign ran from June to July 2026: YouTube ads, taxi signage, and outdoor advertising at Tokyo and Otemachi stations (2026-07-07).
• Of the 32 PR TIMES releases dated 2026-01-16 to 2026-09-18, 17 are product feature or template updates. The rest are awards (5), case studies (4), events (3), appointments and hires (2) and an advertising campaign (1) (PR TIMES company page; accessed 2026-10-11).

Resources

Official

• Corporate site (JA) · About / company profile · Clients · Case studies · News index
• Product pages: index · 案件管理 · 契約管理 · データベース · AI契約アシスタント · AI Agent
• ISMS certification notice, 2024-03-22 (JA) · NEXTユニコーン調査2024 notice, 2025-01-17 (JA)
• Column: NO&T and MNTSQ founding story, 2025-03-03 (JA)
• MNTSQ AI Agent release on the company site, 2025-09-19 (JA)
• Careers site (JA) · Engineering careers page (JA)
• HRMOS job board (JA): Tech Lead · Lead Engineer (Backend) · Lead Engineer (Frontend) · Design Engineer · Software Engineer (Backend) · Software Engineer (Frontend) · AI (NLP) Engineer · 制度企画・労務
• Tech Blog (JA) · archive — GCP Workload Identity Federation, 2026-09-29 · Search for legal work, 2026-09-09 · Elasticsearch to OpenSearch, 2026-08-26 · Celery + SQS, 2026-06-29 · Redis to SQS, 2026-05-11
• note (JA) · connpass
• Speaker Deck — Engineering Team Deck, 2026-09-01 更新 (JA) · LT: replacing contract analysis with LLMs, 2024-07-11 (JA)
• Wantedly post by 堅山, 2019-10-29 (JA)
• GitHub organization MNTSQ

Press releases (PR TIMES, JA — newest first) · company page

• AI Agent phase 3: contract review in Word — 2026-09-07
• Microsoft Teams integration — 2026-09-01
• Slack integration — 2026-08-06
• E-signature integration extended — 2026-07-23
• ITreview Grid Award 2026 Summer — 2026-07-15
• 2,000 adopting companies; first media campaign — 2026-07-07
• HR's SDGsアワード2026 — 2026-06-29
• Templates: 13 added incl. AI service terms — 2026-06-18
• Public API: ISO 8601 date format — 2026-06-16
• Tokyo Electron case study — 2026-06-04
• COO appointment (深井 亮) — 2026-06-01
• CEO receives FT Legal Intrapreneur award — 2026-05-22
• Counterparty management with NTA master — 2026-05-19
• Algorithm engineer 内海 慶 joins — 2026-05-12
• Public matter-management API — 2026-04-07
• AI Agent in 案件管理 — 2026-03-05
• Multi-language contract analysis — 2026-01-21
• Template line-up doubled — 2026-01-16
• Nikkei 2025 ranking: 9 of top 10 — 2025-12-24
• ISO 4217 currencies — 2025-12-16
• Office move to Harumi Triton Square — 2025-10-09
• Itochu adopts MNTSQ CLM — 2025-10-08
• Kanpo–Aflac–Japan Post accelerator — 2025-08-15
• AIリーガルテック協会 symposium — 2025-07-09
• 案件フロー feature — 2025-06-30
• Mori Hamada & Matsumoto capital and business alliance — 2025-05-07
• AI契約アシスタント orders open — 2025-03-19
• Nishimura & Asahi strategic collaboration — 2024-06-04
• ¥1.0B via three CVCs, bond and loan — 2024-06-03
• AI契約レビュー release — 2024-02-28
• English UI — 2023-10-02
• Series B, ¥1.0B — 2023-09-19
• MNTSQ AI契約レビュー development announced — 2023-09-19
• Hitachi adopts MNTSQ CLM — 2023-08-09
• Generative AI/LLM development team — 2023-06-05
• RubyKaigi 2023 Ruby Sponsor — 2023-03-06
• Office move; 50 members — 2022-07-19
• Mitsubishi Electric adopts full line-up — 2022-01-26
• 案件管理 announced — 2022-01-26
• 稲葉総合法律事務所 adopts MNTSQ — 2021-12-22
• SMBC syndicated-loan drafting — 2021-11-01
• Zuva DocAI integration — 2021-09-30
• Mitsubishi Corporation — 2021-06-30
• CloudSign integration — 2021-04-14
• MNTSQ for Enterprise release — 2020-12-07
• PoC with Komatsu and Fukuoka Bank — 2020-06-10
• NO&T partners join board — 2019-11-13
• NO&T and PKSHA capital and business alliance, ¥800M — 2019-10-21

Third-party coverage and profiles

• NTA corporate number register — 7010001196433 (JA)
• Preferred Networks leadership — 堅山 耀太郎 biography (JA)
• BRIDGE — 2024 round, 2024-06-04 (JA)