Are you being asked, “Can’t AI make this faster and cheaper?”
Sony Payment Services
Payments & authentication
Japan Post
Large-scale business systems
A JR-group station building operator
Operations & customer-facing systems
Sony Group
Technical consulting / business & investment planning
Kappa Sushi
Payments & O2O (dining)
MASH Holdings
Payments & O2O (apparel)
World Co., Ltd.
Payments & O2O (apparel)
All About
Web system development
Kinko's Japan
Store & order systems
“We get vendor proposals, but can’t judge whether they really fit us. We keep ordering at the quoted price.”
“We were told AI would make things better — what we got is confusion and cost overruns.”
“Legacy systems are so entangled we don’t know where to start. The team is wearing down.”
A tangle of systems
example
We help you avoid the most common ending: tools nobody uses. We use Claude Code and Codex across all of our own product development and publish our spec-driven workflow as open-source Agent Skills. We rescued a stalled identity-platform project by switching it to AI-driven development, shipping with half the originally planned resources and schedule.
View the OSS: anyoneanderson/agent-skillsWe reduce the risk of breaking what works through assessment and staged migration plans. Deciding what to rebuild and what to keep takes both engineering judgment and investment judgment.
We take on domains nobody else will — starting from the research. DID/VC was one of them: we learned it after being asked, went from studying the standards to designing patent-worthy use cases to building the platform, and became a named inventor on a registered patent (JP7857517) for AI-agent authority delegation. Bringing an unknown domain up to decision-and-implementation grade is what we do.
Fifteen years of payment and O2O systems for Sony Group (consulting), JR-affiliated station retail, Kappa Sushi, Japan Post, and others — including compliance with enterprise security standards and third-party penetration testing. We know how to build systems that must not stop.
Start small
Start here60-minute consultation
JPY 30k–50k
AI adoption, technology selection, team structure
AI-Driven Development & Modernization Assessment
JPY 300k–800k
System and process inventory, risk analysis, improvement plan
Project engagements
AI development workflow adoption
JPY 800k–2M
Claude Code / Codex and CI/CD, from rollout to adoption
PoC / MVP development
JPY 1.5M–5M
Rapid validation of new business, AI, and Web3 products
Ongoing engagements
Technical advisory
JPY 300k–800k/mo
Design reviews, technical consultation, direction setting
Fractional CTO / architect
From JPY 1.5M/mo
Acting technology lead: team building, vendor management, key decisions
Independent review
Technical due diligence / vendor review
JPY 800k–3M
Third-party review of code, architecture, team, estimates, and debt
Prices are indicative ranges; a formal quote follows the consultation.
Case 01
A next-generation identity platform (DID/VC) had stalled in its first iteration. We redesigned the architecture and switched to AI-driven development, shipping the current version with half the original resources and schedule.
Case 02
Requirements definition through delivery management for payments and O2O systems at major station-retail, apparel, restaurant, and postal enterprises.
Case 03
For Sony Group and others, our consulting covered not just system design but business plans and investment plans for new ventures.
Case 04
When AI writes the code, productivity and roles change. Drawing on published experiments from engineering organizations such as OpenAI and the practice of harness engineering, we advised on how evaluation and team structure should evolve.
Read: An introduction to harness engineering
Keita Sunaga
Representative, ZenChain LLC / CEO, Samurai Inc.
Patent
Co-inventor of JP7857517 (authority delegation to AI agents)
Columns
@IT (solo) and ITmedia (co-authored)
OSS
Spec-driven development Agent Skills (anyoneanderson/agent-skills)
Started as an engineer building ATMs, led e-commerce package development at Digital Garage, then joined e-Cash Inc. (now Pass Co., Ltd.) as board director and executive officer, where he experienced a TSE Mothers listing during his tenure. Founded Samurai Inc. in 2010, received investment from Sony Payment Services, and completed a buyout to NONENTROPY JAPAN in 2024. He has now run the company for 15 years.
Never choose technology on engineering taste alone; never impose business logic that the team can't build. Having been through an IPO as a director and a capital alliance and buyout as a founder, standing between those two perspectives is the job.
Bring it before it’s fully formed.
Book a 60-min consultation