http://www.dtic.mil/dtic/tr/fulltext/u2/672483.pdf I accidentally found the attached army Technical Report produced in the middle of the Vietnam War. It’s kind of interesting. My comments: The Army had a “Limited Warfare Laboratory” or LWL. I wonder what kind of machete the “All Out Warfare Laboratory” would have produced. Compare the quality and approach of this document to those produced today. It is relatively brief and sticks to the facts. Apparently the genesis of this effort was the fact that the GI machete was a bit much for jungle trail cutting, and GI’s were altering them to be lighter. It has a square tip and a long unsharpened “ricasso” or “throat” (for an extra hand grasp area) with digging in mind. The field unit recommended a larger cutting edge; one could infer they preferred more cutting edge over “improved” digging ability. The shape looks kind of like the British Army pattern. The LWL wasn’t afraid to try new things (chisel grind combined with tungsten carbide coating, a tungsten carbide plated steel sharpener, and a new scabbard), and also wasn’t afraid to discard those that didn’t work out, or to accept user criticism. They sent machetes out to a unit engaged in the field for their feedback. It reminds me of the Boards the frontier West army used to evaluate equipment. The operating instructions were one sheet long. It would probably take a field manual today.