The Macuahuitl was a warclub/sword hybrid which is thought to have been developed by the Aztecs some time after their migration to Central Mexico.
The body of the Macuahuitl was made entirely of hardwood which then had grooves cut into both sides. Using adhesive, sharp obsidian blades were affixed into the grooves. A leather strap was fastened to the bottom handle loop, and the users hand fit through the strap. The Macuahuitl was unbalanced and front heavy, which made losing the weapon during a swing a real risk. The strap ensured that the user could keep their weapon even if they lost grip.
The blades were broken off of entire obsidian cores, meaning that the blades didn’t have to be sharpened or “knapped”. Rather, they broke off of the core in an extremely sharp state. Many natives encountered by the Spanish conquistadors used these blades for shaving, and the Macuahuitl swords were supposedly so sharp that they could decapitate a horse with one swing, a daunting task even with a steel sword (Castillo).
The Macuahuitl was not used by commoners in battle. Rather, it was a tool restricted to warriors of merit and the nobility. This is likely because the weapon requires a level of martial prowess and skill to use effectively in battle. Most versions of the Macuahuitl could only be swung, not stabbed, meaning that if a warrior missed his strike, he could potentially leave himself undefended. As such, the Macuahuitl is almost always shown as paired with a shield. Some depictions of the Macuahuitl show a triangular obsidian blade affixed to the top of the wooden shaft, allowing the user to stab with the weapon. This grants a significant advantage in battle, but this variant of the Macuahuitl was likely more cumbersome to carry around; the most comfortable resting position for a fairly heavy wooden weapon like a Macuahuitl is to hold it with one hand and rest the top of the weapon on the ground. A swordsmen of the day would have to be careful if he had a Macuahuitl sword with a stabbing spike; the sharp, fragile blade could brake if he hit the ground hard enough with it.
In addition, the nature of the weapon as a “hack and slash” tool meant that unit formations had to be loose. Adequate space between soldiers was the only way to ensure that combatants had enough room to swing their swords without hitting allies. The Toltecs had previously invented a shortsword for combat, but Hassig and others classify the Macuahuitl as a broadsword because of its length and size. Battlefield conditions change over time and in this case a larger, longer sword was necessary for battle. The weapon also came in a two handed longsword variation.