Within the bodygraph, the composite body-map at the centre of Human Design, Gate 21 is placed in the Heart/Ego/Will centre, one of the nine centres the system maps onto (and expands from) the seven-centre chakra model. Gates do not act alone in the model: each pairs with another gate to complete a channel joining two centres. It belongs to the Channel of Money (21-45), which it forms with Gate 45 ("The Gatherer"). These placements and pairings are features of Ra Uru Hu's 1987 design and describe the system's internal mechanics; they are presented here as the system's own claims, not as verified facts about human beings.
Human Design's own teaching connects Gate 21, control of resources, to its I Ching correspondent, Hexagram 21, Biting Through, whose received image is an open mouth biting through an obstruction lodged between the teeth; the system carries that image into a gate concerned with asserting control over materials and resources within one's own domain, paired with Gate 45 in the Channel of Money, which the system reads as the material governance of a group's resources. Gate 21's placement in a chart also depends on the Rave Mandala, the wheel of all sixty-four gates arranged around 360 degrees; since 360 divided by 64 is 5.625, each gate spans exactly five and five-eighths degrees of zodiacal arc, and it is the Sun, Earth, Moon and other bodies' positions at birth and at a second, pre-birth moment that the system uses to determine which gates a given chart activates.