Math is definitely not my strong point but I did a little to try to answer some questions I’ve been getting about the Japanese line rating system for fluorocarbon level lines and what it translates to in diameter. Please note: lb. test is irrelevant. Diameter matters more for turnover than test. And, test per diameter varies from company to company so I narrowed it down to the most relevant and popular diameters for tenkara. Also keep in mind that these are approximations that seem to have consensus. But some companies’ ratings might slightly vary outside these diameters. Anything outside this range is specialty and I don’t think applies to most of us so I didn’t include it. I hope this helps.