What are the differences in J.A. Henckels knife construction?

J.A. Henckels knives are constructed in several different ways. Listed below is a brief look some of these processes.

SIGMAFORGE

SIGMAFORGE is the standard which the top J.A. Henckels "TWIN" series knives are constructed. These series include: TWIN Select, TWIN Four Star II, TWIN Five Star, TWIN Pro "S", and Four Star. SIGMAFORGE knives are precision forged from a single piece of Henckels exclusive high carbon, no-stain steel formula. The results are exceptional...they include:
-Perfect geometry of the entire knife
-Higher stability of the blade
-Less metal fatigue - improved steel structure
-Improved cutting-edge retention
-Lasting sharpness
-Improved quality consistency
-Improved weight and balance
-FRIODUR ice-hardened blades

TRADITIONAL HOT DROP FORGED

The TWIN Cuisine knife series from J.A. Henckels is hot drop forged in a more traditional method due to the horizontal design of the knife's tang. With this process, TWIN Cuisine knives are also constructed from a single piece of exclusive Henckels high carbon, no-stain steel. The outstanding results are:
-Heavy weight, durable feel through the entire knife
-FRIODUR ice hardened blades
-A uniquely designed knife with perfect ergonomics

STAMPED
With this process, knives are formed out of a single sheet of steel. Basically, knives are stamped out of the steel sheet. The quality of the steel, tempering process, and finishing results in a quality knife. J.A. Henckels' TWIN Signature and TWIN Gourmet are maunfactured in this way, and the blades are FRIODUR ice-hardened.