One of the first true folding fighting knives, The Navaja was developed in Spain. The style allowed for large fighting knives to be retracted into the handle (as opposed to being worn in a scabbard on the belt). Blade lengths varied from 8 to 12 inches. Gravity was the primary activator (involving a simple wrist flick to either partially or fully extending the blade). Due to no real standard issue, The Navaja Knife was normally privately procured and used by The Spanish Military. Handles were also a matter of taste. Wood, bone or pearl handles are known to exist. The blades were designed to be very sharp and were always single-edged. They often featured a slimmer, tapered top blade portion (that was reinforced by a straight broader pattern (extending back to the handle).