Sensor-Type Ninja

A sensor type is a ninja that is capable of detecting the presence of others. There are several methods of sensing, but the most common one is through a target's chakra.

A skilled sensor can detect their targets from a great distance, as well as differentiate people by their signature alone. They are even able to tell when other sensors are using their abilities. Karin Uzumaki is able to tell exactly who is among a crowd of people and her sensory skills are such that she is even able to tell if her targets are lying based on any fluctuation of their chakra. The Senju Family have displayed that sensors can discern between chakra signatures of shinobi from different populations and even link them back to relatives; for example Teruko Senju commented that Taiyou and her brother, Yasha, shared similar chakra signatures, while Furostomi Chinoike was able to discern that Teruko was descended from the Senju. Nagato, another skilled sensor, was able to detect the exact location of the person controlling them despite that person erecting a barrier around themselves. Members of the Yamanaka have even displayed a technique whereby sensory perception can be transferred to other non-sensors.

Conversely, there are methods that can hinder a sensor's ability to detect individuals. Karin is able to suppress her chakra completely, though she cannot use her abilities while doing this. In the anime, sensor types have different specialties depending on their villages. Karin's sensing abilities are derived from her Mind's Eye of Kagura; it is unknown if other sensors also have a specific techniques to do so, or if it is just a general skill.

Sensor types can also detect changes in a person's personality by sensing their chakra as chakra reflects the user's personality. To be able to sense an opponent, a shinobi must have their chakra to "sensory mode". As such, if they are distracted and don't have their chakra on sensory mode, they can be kept from detecting enemies. Various individuals have commented on the "feel" of a person's chakra and similar comments regarding the ability to sense high levels of chakra a little, leading to the possibility that chakra sensing is merely a more refined version of this by either teaching or being simply born more sensitive to it.

Trivia

 * Sages, who utilise natural chakra, can also detect the presence of people through their chakra, granting them sensor abilities. Also, Nagato was able to reverse track Kabuto when he emitted his chakra through their control tags of the Impure World Reincarnation and Naruto was able to do the same thing to Nagato with the chakra stakes.
 * Sasuke claimed that Karin's ability to sense chakra is unlike that of anybody else.
 * Some dojutsu can cause sensor abilities, like the Jougan, Byaku-Sharingan, Byakugan and Sharingan.
 * Furostomi Chinoike inherited Karin's technique; the sensor type can also pick up any vibrations of movement or chakra flares using the Eye's MInd of Kagura technique also while using Chijagan.
 * A few Nara clan members, like Hayato Nara, can sense enemy ninja through their shadows.

See Also My Dudes:
List of Sensor Type Ninja

List of Ninja with Dojutsu