Ninjas, also known as shinobi, practiced a martial art called "Ninjutsu" or "Ninpo." Ninjutsu is the martial art associated with the skills and techniques employed by the historical ninja in Japan. It encompasses a wide range of tactics, strategies, and combat techniques that were developed for espionage, sabotage, guerrilla warfare, and self-defense.

Ninjutsu involves a combination of unarmed combat techniques (taijutsu), weapon handling, stealth, disguise, escape and evasion tactics, intelligence gathering, and various specialized skills such as lock picking, explosives, and poisons. The focus of ninjutsu was not solely on direct confrontation but also on effective covert operations and survival in various situations.

It's important to note that the historical practices of ninjutsu have evolved over time, and today, various modern martial arts schools and organizations teach different interpretations of ninjutsu. These modern interpretations often blend traditional martial arts techniques with the historical principles and strategies associated with ninjas.