Within the bodygraph, the composite body-map at the centre of Human Design, Gate 3 is placed in the Sacral 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 Mutation (3-60), which it forms with Gate 60 ("Acceptance Of Limits"). 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.
The Sacral centre carries a specific function in the system's own account: life force and work energy, read as the body's own generator and its yes or no gut response. Gate 3 is one of 9 gates the bodygraph assigns to this centre, and its reading is built from that placement rather than from anything in the classical hexagram commentary.
The same number appears elsewhere in this atlas as Gene Key 3, Richard Rudd's later, contemplative rereading of the identical hexagram. Where Ra Uru Hu gives the gate the fixed keynote "Ordering Through Difficulty", Rudd spreads the same number across a spectrum: the Shadow of Chaos, the Gift of Innovation and the Siddhi of Innocence. The two accounts share a hexagram and a number and diverge in almost everything else, since one issues a fixed mechanical reading and the other asks for years of contemplation.