Col. Coutrot

Pictured above: The bayonet from a Lebel Model 1886 rifle.
The bolt-action Lebel served as France's main battle rifle from 1887 to 1940 even though it was made obsolete shortly after its adoption.
It was however, the very first rifle, designed for smokeless powder, that was adopted by a major military power. The 8mm Lebel round was also the first to use a boat-tailed bullet in 1901.
Innovations notwithstanding, the round itself was the Lebel's undoing. The rifle itself was rugged and dependable. But, when it was designed the decision was made to simply neck-down the existing 11mm cartridge to 8mm. This resulted in one of the weirdest looking bullets to come down the pike. Stubby, with a thick rim that was twice the diameter of the projectile. This made it difficult to feed or convert to automatic fire and is why the magazine of the notorious Chauchat looked as it did.
But, it out-classed everything else at the time - for a while. As far as the ballistics went, it fell somewhere between the .303 British and the 8mm Mauser, both of which showed up a few years later. Hence the early obsolescence of the Lebel.
But this is about the bayonet: a slender cone of steel, twenty-plus-inches long with four grooves milled into its length. This resulted in a cruciform cross-section meant to penetrate enemy great-coats and leave a slow-to-close wound. The look of the wound prompted the Poilus to call it “la Rosalie" ("The rose"), charming.
Well, it didn't take a genius to see that a bayonet nearly two feet long wasn't going to work in the trenches, so some lads started to make modifications. Above: Two such daggers, one of which retains its bayonet clip. Multi-functional, non?

This next is thrown in just for the hell of it. A Lebel bayonet handle with what looks to be a French Nail mounted in it.
Enter, Lt Colonel Coutrot who set about supplying the French troops with trench daggers.

He determined that three daggers could be produced from one bayonet.
Above is number one, taken from the base.


The mid-section gives us number two.
























You knew this was coming. The final dagger was simply the pointy six final inches.
As you can see, thin, steel, oval-shaped guards and functional handles made from good old indestructible beech.
The various handle shapes are due to the different cutlery firms contracted to do the conversions.
Of course, all good things must come to an end. The supply of 1886 Lebel bayonets wasn't unlimited.
Coutrot, having established the manufacturing infrastructure, designed the following double-edged dagger (I guess that's redundant): The Coutrot "Number Four".
Terminologies can be clarified (maybe) at this site. It's in French but you can get a Google translation and it alone is worth the price of admission. I reads like Chinese stereo instructions. "Poilu" is, at one point, rendered as "Furry". Close enough, I guess.
But I digress; All this is building toward something.
Waiting in the wings, primed by all this bayo-based R&D, the knife informally known as the "Le Vengeur de 1870".

There will be no bailing-out of any who may be too historically dim as to not get the reference to 1870. Google is your friend.

Formally, it's moniker was more a bit more of a mouthful:
"Couteau Poignard Mle 1916." Issued to the French Army until 1939.
But it's all about me - as usual.
My version of "Le Vengeur".