Pesquisa

is an advanced Arrancar perception technique which is used to both detect and gauge sources of Reiatsu within the vicinity of the user.

Description
Pesquisa functions similarly to sonar, through a radiating pulse sent outwards from the user which reacts to sources of Reiatsu within a certain proximity, allowing them to determine the location of any sensed individuals and granting them an indication of how powerful they actually are. When the ability was first performed by Grimmjow Jaegerjaquez alongside his Fracción, each closed their eyes and entered into a meditative state of mind in order to attain the necessary heightened sense of awareness.

Out of all those shown using this technique, including two other members of the Espada, Ulquiorra Cifer seems to be the most adept with it, being able to precisely determine the level of an opponent's Reiatsu with just a mere glance. Despite this, the Sonído of Hollow Ichigo's new form strangely allowed him to pass through Ulquiorra's Pesquisa without him noticing.