A knife fight is a violent physical confrontation between two or more combatants in which one or more participants is armed with a knife. A knife fight is defined by the presence of a knife as a weapon and the violent intent of the combatants to kill or incapacitate each other; the participants may be completely untrained, self-taught, or trained in one or more formal or informal systems of knife fighting. Knife fights may involve the use of any type of knife, though certain knives, termed fighting knives, are purposely designed for such confrontations – the dagger being just one example.
During the long history of the knife as a weapon, many systems or schools of knife fighting have developed around the world. Each is usually distinguished by region and culture of their origin. In past centuries the repeated invasion and conquest of foreign territories by invading armies frequently resulted in the dissemination and adoption of knives and knife fighting techniques. These were in turn adapted and improved upon through long practice and drills, sometimes over hundreds of years.
The Italian stiletto, originally a purely offensive weapon used to kill an unsuspecting or wounded adversary, was later embraced throughout Italy as a fighting knife for close combat confrontations. The popularity of the stiletto in the Kingdom of Sicily resulted in the development of the scherma di stiletto siciliano (Sicilian school of stiletto fighting). The stiletto was purely a thrusting or stabbing weapon, and the scherma di stiletto siciliano accordingly taught fighting movements designed to avoid the tip of the opponent's blade (scanso). Techniques characteristic of the scherma di stiletto siciliano include sbasso (bending to ground), in quarto tagliata (tacking to left or right), and the balzo (leap to evade the enemy’s blade). A person skilled in the use of a stiletto would thrust the knife deep into the victim, then twist the blade sharply in various directions before retracting it, causing the sharp point to inflict severe internal damage not readily apparent when examining the entrance wound.
In Andalusian Spain, the use of the large navaja (folding knife) as a fighting knife has been prevalent among the peoples of that region since the 17th century. In that part of Spain, sword and knife fighting techniques (espada y daga) were regularly taught to young men as a necessary skill, often passed down from father to son as a rite of passage to adulthood (and in some cases, to daughters as well). In 18th- and 19th-century Spain esgrimas de navaja (fencing, or knife-fighting schools) could be found in the major cities and throughout Andalucía, particularly in Córdoba, Málaga, and Seville. As time went on, these schools began to depart from teaching traditional sword-fighting and fencing techniques in favour of simplified attacks and defences based largely on the concept of deception, distraction, and counterstrike. Among navaja aficionados, the gamblers or barateros of Málaga and Seville were cited as the most skilled practitioners of fighting with the navaja. The firmly-established knife-fighting tradition with the navaja in Andalusian Spain would later spread to other Spanish-speaking countries, and was known as el legado Andaluz, or "the Andalusian legacy".