Physical
Ju-Jitsu defence against a knife attack. Berlin 1924
Physical self-defense is the use of physical force to counter an immediate threat of violence. Such force can be either armed or unarmed. In either case, the chances of success depend on a large number of parameters, related to the severity of the threat on one hand, but also on the mental and physical preparedness of the defender.
Unarmed
Many styles of martial arts are practiced for self-defense or include self-defense techniques. Some styles train primarily for self-defense, while other martial or combat sports can be effectively applied for self-defense. Some martial arts train how to escape from a knife or gun situation, or how to break away from a punch, while others train how to attack. To provide more practical self-defense, many modern day martial arts schools now use a combination of martial arts styles and techniques, and will often customize self-defense training to suit the participants' lifestyles, occupations, age groups and gender, and physical and mental capabilities.
Armed
Further information: Non-lethal weapon and Melee weapon
A wide variety of weapons can be used for self-defense. The most suitable depends on the threat presented, the victim or victims, and the experience of the defender. Legal restrictions also greatly influence self-defence options.
In many cases there are also legal restrictions. While in some jurisdictions firearms may be carried openly or concealed expressly for this purpose, there are also jurisdictions with tight restrictions on who can own firearms, and what types they can own. Knives, especially those categorized as switchblades may also be controlled, as may batons, pepper spray and personal stun guns and Tasers - although some may be legal to carry with a licence or for certain professions.
Non-injurious water-based self-defense indelible dye-marker sprays, or ID-marker or DNA-marker sprays linking a suspect to a crime scene, would in most places be legal to own and carry.
Everyday objects, such as flashlights, baseball bats, newspapers, keyrings with keys, kitchen utensils and other tools, and hair spray aerosol cans in combination with a lighter, can also be used as improvised weapons for self-defense. Tie-wraps double as an effective restraint. Weapons such as the Kubotan (pocket stick) have been built for ease of carry and to resemble everyday objects. Ballpoint pen knives, swordsticks, cane guns and modified umbrellas are similar categories of concealed self-defense weapons that serve a dual purpose.
Mental
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Mental self-defense is the ability to get into the proper mindset for executing a physical self-defense technique. Many martial arts schools and self-defense classes focus primarily on the physical nature of self-defense and often neglect the mental aspect. If you are skilled in the physical aspects of a defensive technique, but lack the mental toughness and tenacity to execute it, you will not be able to perform - especially under duress. Controlled environments cannot easily mimic the stress and adrenaline dump which occurs during an attack. There is a very real need to be able to enter the proper "warrior mindset" if one is to have a realistic chance of surviving a potentially deadly encounter. This warrior mindset is the ability to focus purely on the successful outcome of a situation without becoming concerned with the consequences, even if they prove fatal in the dedicated pursuit of your desired outcome. The ability to go over, under, around or through any obstacle is the essence of this "never quit" mindset - similar to that of the Samurai of Japan. Self-preservation is a very powerful motivator and it is essential for ensuring that one has the mental toughness and proper mindset to emerge the victor in an encounter with one or more attackers/aggressors.