The engineers at Gamakatsu use high-carbon steel to form the wire the hook is made from because steel with a high carbon content is much stronger and harder and since it is harder it can be sharpened to a much finer point. Some of the best and sharpest knives in the world are made from high-carbon steel for the same reason. After the wire is drawn it is cut and formed in the hook shape and tempered using a high-tech electronic heating process and then quenched in oil to bring out the perfect balance of hardness and flexibility. Hooks that are too hard are brittle and will break under high stress and hooks that are too soft will bend and straighten out under a load and not hold a good point.
Since high-carbon steel can corrode or rust easily these hooks are finished with black or bronze anodizing or tinned producing the distinctive colors Gamakatsu hooks are available in today. The excellent quality control and high tech facilities that Gamakatsu uses ensures a high level of consistency from hook to hook and year to year so you can be confident the hook you take out of the pack you bought and tie on will be the best possible hook or it wouldn't have the name: Gamakatsu.