CQC-6

The CQC-6 (Close Quarters Combat — Six) or Viper Six is a handmade tactical folding knife with a tantō blade manufactured by knifemaker Ernest Emerson and is credited as the knife that popularized the concept of the tactical folding knife.

In the mid-1980s, individual Navy SEALs from a West Coast team had been using personally purchased custom fixed-blade knives made by Southern California knifemaker Phill Hartsfield.

Hartsfield's knives are hard ground from differentially heat-treated A2 tool steel and are known for their distinctive chisel-ground blades. More accurately, they are zero ground; that is, the edge has no secondary bevel, minimizing drag when used for cutting purposes.

Emerson had long been impressed by the cutting ability of the chisel-ground edge and had asked Hartsfield's permission to incorporate it into his own folding knives, which Hartsfield granted.

When the SEALs asked Hartsfield to make them a folding knife, he informed them that he did not make folding knives and referred them to Emerson who manufactured folding knives utilizing the Walker linerlock.

Emerson's folding chisel-ground "tantō" became the sixth model in his Viper series and, while a handful of prototypes were referred to as "Viper 6", the model was soon named the "CQC-6" (CQC refers to "close-quarters combat") and was chosen by the SEALs for use.

Writer, David Steele, refers to the CQC-6 as the sixth model after five prototypes as opposed to the next in the evolution of the Viper line of knives. Emerson, himself, says the moniker "six" was used because the SEALs in question were members of SEAL Team Six.

According to the SEALs' requirements, the knife had to be corrosion resistant, designed for easy cleaning in the field, durable enough to be used on a daily basis as a tool, and capable as a weapon should the need arise.