example) which may allow for an easier throw. Many sayings about are attributed to Morihei Ueshiba, who considered them an essential element of technique. Weapons Weapons training in aikido traditionally includes the short staff () (these techniques closely resemble the use of the bayonet, or Jūkendō), the wooden sword (), and the knife (). Some schools incorporate firearm-disarming techniques, where either weapon-taking and/or weapon-retention may be taught. Some schools, such as the Iwama style of Morihiro Saito, usually spend substantial time practicing with both and , under the names of , and , respectively. The founder developed many of the empty-handed techniques from traditional sword, spear and bayonet movements. Consequently, the practice of the weapons arts gives insight into the origin of techniques and movements, and reinforces the concepts of distance, timing, foot movement, presence and connectedness with one's training partner(s). Multiple attackers and One feature of aikido is training to defend against multiple attackers, often called , or . Freestyle practice with multiple attackers called is a key part of most curricula and is required for the higher-level ranks. exercises a person's ability to intuitively perform techniques in an unstructured environment. Strategic choice of techniques, based on how they reposition the student relative to other attackers, is important in training. For instance, an technique might be used to neutralise the current attacker while turning to face attackers approaching from behind. In Shodokan Aikido, differs in that it is not performed with multiple persons with defined roles of defender and attacker, but between two people, where both participants attack, defend, and counter at will. In this respect it resembles judo . Injuries In applying a technique during training, it is the responsibility of to prevent injury to by employing a speed and force of application that is appropriate with their partner's proficiency in . When injuries (especially to the joints) occur, they are often the result of a misjudging the ability of to receive the throw or pin. A study of injuries in the martial arts showed that the type of injuries varied considerably from one art to the other. Soft tissue injuries are one of the most common types of injuries found within aikido, as well as joint strain and stubbed fingers and toes. Several deaths from head-and-neck injuries, caused by aggressive in a hazing context, have been reported. Mental training Aikido training is mental as well as physical,