I'm Toshikatsu Oga — middle-school dropout, 30-year veteran carpenter from Japan. Self-taught AI in 1 year. Published cryptographic audit hash paper on engrXiv and anchored to Bitcoin Block #949356. HORIZON SHIELD protects homeowners from quote fraud with verifiable 12-char audit hash. Paper: https://engrxiv.org/preprint/vie... Live: https://shield.the-horizons-inno... From dirt-covered hands to immutable code.

I spent 30 years in Japanese construction — carpenter, site supervisor, CM. I watched homeowners get systematically overcharged. HORIZON SHIELD uses AI to diagnose construction cost estimates. Upload a quote photo and get a diagnosis in 30 minutes. Real case: found ¥500,000 in overbilling on a ¥3,800,000 quote. Backed by Japan's first open construction cost database (87 plans, 88 fraud patterns, CC-BY 4.0) on Zenodo and GitHub. Free AI diagnosis via ChatGPT and LINE.