Dean is right. Nothing, and I mean NOTHING on the Vietnam Tomahawk is there by chance. Peter experimented with endless design concepts to get what he wanted. In fact, about a year ago, I asked Peter what he would do to improve the Vietnam Tomahawk design. "NOTHING!" he said, and looked at me like I was derranged for asking. I bowed my head in obedience.
Peter LaGana prototyped his Tomahawks over the years with Meat Cleavers. Why? Because they "chop" flesh...and lots of it.
Most cleavers are indeed straight edged...massive cutting contact, massive cutting force distributed uniformly over its length, yielding massive effect.
The Vietnam Tomahawk had to fight, as well as dig, chop, pry, etc..
While the edge is straight, it is not parallel to the handle. It is offset, so the top point bites first...then the force driving the head efficiently deepens the bite, as the edge stays in the cut longer because of the offset.
Every impact cutting tool I have seen in industry, such as blanking blades on machinery, have offset, straight cutting edges. On a straight "chop", I don't think it gets more efficient that that.
Hope this helps...