The SOG knife was designed for, and issued to, covert Studies and Observations Group personnel during the Vietnam War. It was unmarked and supposedly untraceable to country of origin or manufacture in order to maintain plausible deniability of covert operators in the event of their death or capture.
The SOG Knife was designed by Benjamin Baker, the Deputy Chief of the U.S. Counterinsurgency Support Office (CISO). A chrome-moly steel known as SKS-3 was chosen for the blade and hardened to a Rockwell hardness of 55-57. The blade pattern featured a convex false edge on the clip point of a Bowie knife. The stacked leather handle was inspired by a Marbles Gladstone Skinning Knife made in the 1920s owned by Baker, into which finger grooves were molded. The blade was typically parkerized or blackened to reduce glare. This was done so by applying a dark gun-blue finish (similar to those used on guns) on this carbon steel knife. The knife was carried in a leather sheath which contained a sharpening steel or whetstone.
The first contract was awarded to Japanese manufacturer Yogi Shokai for 1,300 seven-inch blades designated "Knife, indigenous, RECON, 7", w/scabbard & whetstone" at $9.85 each. In 1966, SOG ordered 1,200 sterile knives with six-inch blades and black sheaths and in March of the following year an additional lot of 3,700 was ordered. This second lot was serial numbered for accountability purposes and was designated "Knife, indigenous, hunting, 6", w/black sheath and whetstone".
In the 1980s a company named SOG Specialty Knives manufactured a knife very similar to the original SOG knife in Seki City, Japan and marked it with the US Army Special Forces Crest., and named it the "S1 Bowie". The other Vietnam replica knife is known as the "Recon Bowie" by SOG and both knives are manufactured to the same specifications and in the same factory as the original Vietnam-era knives. The last replica knife is the "SCUBA/Demo".
SOG made a version with a stainless steel blade and micarta in commemoration of the U.S. Navy SEALs., known as the "SOG Trident". Replicas of the SOG knife have been made by Al Mar Knives, Ek Knives, and Strider Knives. None of these knives, however, are currently used by any branch of the US Military in an official capacity. Original models are valuable collector's items among both knife collectors and militaria collectors.
- Gallery of SOG knives
- SOG S1 Bowie - Information on the replica of the SOG Knife (Manufactured by SOG Specialty Knives) used by MACVSOG Forces in Vietnam
- Pacella, Gerard (2002), 100 Legendary Knives, Iola, USA, Krause Publications, p 99. ISBN 0-87349-417-2.
- Baker, Ben (1991). "Saga of the CISO/SOG Recon Knife". Fighting Knives 1 (3): 95–98.