ChillStack
2 known investors
Tokyo-based AI security company developing fraud/anomaly-detection AI and technologies to protect AI systems.
Also known as 株式会社ChillStack
Founders & leadership
Investors · 2
Company profile
researched Aug 2026ChillStack (株式会社ChillStack) is a Japanese AI security company headquartered in Shibuya, Tokyo, that combines artificial intelligence with security engineering. Its stated positioning is to support societal innovation with advanced AI and security technology, and it organizes its activities into three business lines: the Stena business, an AI Safety business, and a national security business.
The company's technical portfolio spans AI for analyzing fraud and anomalies in time-series and multi-dimensional data, explainable AI (XAI) techniques that visualize how AI models reach decisions, methods for assuring the safety of AI, red-teaming techniques that test attacks against AI-based systems, and technologies for operating AI-embedded systems securely. Public technical writing covers topics such as MITRE ATLAS updates, a prompt-leaking technique against code agents, and an "Agent-Native Immune System" framework for safe AI agent use.
ChillStack was founded in November 2018 and is led by co-founder and CEO Michiaki Ito. The leadership team also includes COO Hiroyuki Nakamichi (business development, with prior BtoB sales, marketing and consulting experience), CTO Hiroki Tani (anomaly-detection AI research and large-scale system development), and Yusuke Chayama, executive officer and head of organizational development, who oversees back-office functions including accounting, labor and legal. The company is a member of the Japan Network Security Association.
Founding story
Founder Michiaki Ito conducted long-running research at the intersection of AI and security, won the best paper award at the international conference IEEE CSPA 2018 and the top prize at the IPA Security Camp Award 2018, won an international security contest, and taught at IPA Security Camp. He founded ChillStack in 2018 after various research and development experience and was selected for Forbes 30 Under 30 Asia 2025 in the AI category.
Business model
ChillStack develops and provides AI and security products and services, grouped into its Stena business, AI Safety business and national security business, and also delivers training jointly with a partner company. Its contact form routes inquiries about services, sales partnerships, LLM security consulting, and AI security for central and local government bodies, indicating enterprise and public-sector sales alongside a reseller/partner channel.
Latest developments
In July 2026 the company published research stating that about 80% of AI-equipped services had insufficient security measures before release even after national AI security guidelines were published, and posted technical analyses of MITRE ATLAS updates, the JustAsk prompt-leaking method, and its Agent-Native Immune System framework. In August 2026 it exhibited at the 5th Back Office DXPO Tokyo '26 Summer (Aug 18-19) and the 2nd IT/Joshis DXPO Tokyo '26 Summer (Aug 20-21), and began offering hands-on AI agent security training together with Mitsui Bussan Secure Directions.
▸Full profile — market position, technology, go-to-market, geography, history
Market position
The company presents itself as an AI security company serving enterprises and government agencies in Japan, describing its work as based on AI security fundamental research and staffed primarily by engineers with experience in the AI security domain, and combining business and technology perspectives.
Technology
Core technologies include AI for detecting fraud and anomalies in time-series and multi-dimensional data, XAI methods for making AI decision processes interpretable, techniques for ensuring AI safety, red teaming to test attacks against AI-based systems, and methods for safely using and operating systems that embed AI. Technical blog topics include MITRE ATLAS updates from June 2026, a prompt-leaking method using code agents called "JustAsk", and an "Agent-Native Immune System" framework for safe AI agent utilization.
Go-to-market
Go-to-market includes direct inquiries and consultations via the corporate site (services, LLM security, government/municipal AI security), sales partner recruitment, exhibiting at Japanese business expos such as IT/Joshis DXPO and Back Office DXPO in Tokyo, publishing research-oriented press releases and technical blog content, and co-delivering hands-on AI agent security training with Mitsui Bussan Secure Directions.
Enterprises deploying AI-enabled systems and LLMs, along with central government ministries and local governments; the site also addresses prospective sales partners and investors.
Geography
Headquartered at Yoyogi Forest Building 2F, 5-18-20 Sendagaya, Shibuya-ku, Tokyo 151-0051, Japan, with public activity such as trade-show exhibitions concentrated in Tokyo.
History
The company was founded in November 2018 by Michiaki Ito after research and development work in the AI and security field. It has since built out a board including a COO and CTO plus an executive officer for organizational development, joined the Japan Network Security Association, and by 2026 was publishing regular press releases, exhibiting at Tokyo trade shows, and running a technical blog and a corporate note account with member interviews and engineer discussions.
Compiled by commissioned research from 6 cited public sources — announcements, filings, and press listed under research sources below.
Timeline · 6
launches, deals, and filingsChillStack and Mitsui Bussan Secure Directions began offering hands-on training covering security techniques for AI agents.
ChillStack exhibited at the second IT・情シスDXPO 東京'26【夏】 on August 20-21.
ChillStack exhibited at the fifth バックオフィスDXPO 東京'26【夏】 on August 18-19.
Company release reporting that roughly 80% of AI-equipped services have inadequate security measures before release, even after publication of national AI security guidelines.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
▸Research sources · 6
primary sources listed
- ChillStackchillstack.com · web
6 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does ChillStack do?
- Tokyo-based AI security company developing fraud/anomaly-detection AI and technologies to protect AI systems.
- Who are ChillStack's investors?
- ChillStack's investors include Colopl Next, Global Brain.