大賀俊勝 (Toshikatsu Oga) ogasurfproject-jpg

Toshikatsu Oga (大賀俊勝)

I spent 30 years on the construction site. Now I build the tools that let the buyer check the price for themselves.

Founder of The HORIZONs K.K., building HORIZON SHIELD: buyer-side construction-cost verification you can recompute, not just trust.

Don't take their word. Recompute it. （その「適正」、売り手ではなく、あなた自身が確かめられる。）

HORIZON SHIELD: buyer-side AI verification for construction and renovation estimates. It reads a quote, checks it against open cost data, and shows the reasoning so anyone can recompute the result.
JCCDB: an open Japanese construction-cost database. CC BY 4.0, DOI-registered, evidence-linked. The public ground truth underneath the verification.
Verification Gate + JIDEC: a conformance checker and a public, append-only verification ledger. You fetch the bytes, recompute the hash, check the record. No trust in me required.
hs-femtech-mcp: the same idea applied to health information. A neutral registry that measures the transparency of femtech and health sources, never their medical truth. Peer review in progress.
Yakumo: a verified contractor directory with zero referral fees. A listing is earned by passing the check, never bought.

All of it is built MCP-native, so an AI agent can call the verification and get a receipt instead of a marketing claim.

Recomputable. Every verdict is reproducible from public bytes with SHA-256. Believe nothing, recompute everything.
Independent. No referral fees, no pay-for-endorsement. A verifier that is paid to recommend is not a verifier.
Honest about limits. Verified means untampered, not re-audited. When I do not know, I say I do not know. Fail-closed by default.