Adaptive‑Curvature‑Blockchain replaces energy‑intensive proof‑of‑work with proof‑of‑optimization. Miners mint blocks by submitting improved solutions to a travelling‑salesman tour; the chain scores each block by how much the proposed tour improves over a baseline and selects the chain with the highest cumulative score. ACB features automatic difficulty retargeting based on recent successes, scoring rules derived from the baseline cost difference and simple API endpoints for status, chain retrieval and solution submission.