Engineering

A cross-chain studio search app covering NOAH, Gateway, PACKS, and BASS ON TOP near Kashiwa Station. Enter date, start time, duration, and group size to see candidate time slots ranked by distance from Kashiwa, with direct links to each studio's booking page.

• ► Manages room data for 40+ stores across 4 chains as static TypeScript
• ► Implements people-to-min-size mapping, ±1h slot generation in 15-min steps, and distance sort
• ► Direct links to each studio's reservation page from search results
• ► Fully functional with no additional backend — Astro SSG + Vite bundling

Led the insourcing of a NetSuite-based accounting system at a TSE Prime-listed healthcare company to eliminate vendor lock-in and cut running costs. Analyzed black-boxed source code, ported it, and rebuilt the dev environment so internal staff can own and extend it.

• ► Reverse-engineered and ported black-boxed vendor source code end-to-end
• ► Rebuilt the development environment from scratch for autonomous in-house operation
• ► Eliminated vendor lock-in; established a sustainable cost-reduction foundation
• ► Significantly reduced incident response lead time

Managed a 100-person corporate intranet replacement program at an IT consulting firm. Built a precision design-review process with an offshore vendor to close language/nuance gaps — core features cut over with zero post-release fixes.

• ► Owned schedule, quality, and budget for a 100-person program
• ► Designed a precision review process that eliminated offshore requirement gaps
• ► Achieved zero post-release defects on all core features at cut-over
• ► Established fully remote PM with structured communication and progress visibility

At the IT subsidiary of a major housing & construction group, led the entire RPA journey end-to-end: stakeholder interviews, problem surfacing, executive proposal and sign-off, PoC at the parent, then rollout across group companies. Delivered ~50 hours/month in group-wide savings.

• ► Self-initiated the RPA proposal to executives with ROI modeling; won adoption
• ► Delivered ~50 hours/month in group-wide labour savings
• ► Reorganized team into specialty squads, significantly raising throughput and quality
• ► Fully automated 10+ routine tasks, eliminating single-person dependency

Maintained and extended a mission-critical production management system for large manufacturing sites at an engineering company in a major chemicals group. Delivered a new inventory (stocktaking) system solo from requirements to release; refactored data-access logic to make key screens 1.2× faster.

• ► Delivered a new inventory system end-to-end, solo, from requirements to release
• ► Refactored data-access logic to make key screens 1.2× faster
• ► Ensured stable operation of a mission-critical manufacturing system
• ► Improved maintainability with Redmine-based issue tracking and documentation

Built and shipped this bilingual portfolio site in 2 weeks using Claude Code as a development partner — from requirements through design, coding, and production deployment on a custom domain. Running at near-zero cost on Cloudflare free tier.

• ► Requirements to production in 2 weeks with Claude Code as dev partner
• ► All pages statically generated — fast loads and SEO-optimised
• ► Japanese / English bilingual with Astro built-in i18n
• ► Near-zero infrastructure cost on Cloudflare free tier

Long-running personal R&D project: an algorithmic trading engine combining ML and statistical models for high-accuracy signal generation. Database optimised with careful index design and query tuning to handle tens of millions of daily-bar records at speed.

• ► Built a prediction engine combining ML and multiple statistical models
• ► Optimised DB (index design + query tuning) for tens of millions of records
• ► Automated signal generation from technical indicators (MA, RSI, MACD)
• ► Backtesting engine for pre-validating strategies before live deployment