Sharp Swords and Sword Sharpness
Surviving sword specimens, the historical instructions for their use, and the descriptions in the record of the injuries they produced, all confirm that Medieval and Renaissance swords were indeed sharp “enough.” But there is no reason to believe that every kind of sword had the same degree of sharpness along the entire length of its blade. Given the great diversity in sword forms and the considerable variety of blade shapes that existed within the Medieval and Renaissance periods, this could not possibly be the case. It is more or less only an assumption people today make based on limited experience. Keep in mind, in past centuries there was no universal “industry standard” of edge sharpness.
Historically, fighting swords encountered all manner of resistant materials and continuously clashed against other blades and weapons. In general, the different portions or divisions of a sword do not all perform the same actions in combat. Accordingly, the geometry of any given blade’s cross-section tends to change along its length. A straight blade for specifically armored combat needs a point that is thicker and thus typically wouldn't have a flatter “cutting edge” for several inches down from the point. While the point of a particular “anti-armor” blade may be thicker in shape and therefore less able to hold a keen edge, the rest of the weapon would certainly not be dull, but honed well enough to deliver the powerful impacts that we know such weapons are capable of causing. After all, no matter how sharp or hard an edge is, it’s not going to slice through “chain-maile” or cut deeply into plate armor. But then, swords didn't have to. They only needed to deliver enough force to injure targets without the blade itself breaking in the effort. So, they weren’t going to be given extra sharp “cutting edges” but rather, edges that held up and performed under expected use.
On top of this, while many sword blades are quite capable of holding finer edges that can be sharpened to a high degree, but they would do so at the risk of those edges becoming much more easily damaged from common impacts and the warding of blows. Better perhaps then to have an edge that holds up to contact where needed and slashes and punctures where it will. Even then, this says nothing about how cross-sectional geometry and blade curvature play a part in a degree of sharpness. Thus, possible sharpness will differ depending on the sword and sometimes may vary along the blade itself.
What’s more, the actions of “half-swording”, or gripping the blade itself to perform specialized techniques, was a regular element of using Medieval and Renaissance fencing. This is something that a “uniform sharpness” will interfere with. But few modern customers purchasing sharpened replica swords will ever attempt vigorous half-swording moves. Yet, they regularly want to do “test-cutting” attempts on soft target materials. So, differentiated-sharpness never really enters into concern. Today’s sword-makers also typically do not bother with “differentiated sharpness”. They essentially give all blades uniform edges regardless of size, shape, length, or geometry. No wonder people often incorrectly assume that all historical swords, like modern knives, must have
been entirely sharpened to the same level regardless.
I’ve handled hundreds of authentic sword specimens of all kinds. Though noting their original edge sharpness is highly problematic after centuries, I’ve not yet seen evidence of the same universal sharpness all along a length. Sometimes the ricasso or strong near the hilt is thicker and may be entirely edgeless. At other times the edge toward the point begins to round off and thicken while others will become even thinner and flatter. On still other blades, whet straight or curved, only part or none of the back edge is fully sharpened. Any of these features might even be found together. On top of this, I've managed to do a considerable number of effective cutting techniques on all manner of target materials using all manner of swords that were sharpened only just enough where I could still grab and hold their edges in my bare hand. So, the reality is that edges, like sword blades themselves, varied from weapon to weapon.