Where the Gates come from
The Gates are the 64 hexagrams of the Chinese “Book of Changes,” laid out around the circle of the zodiac: each one gets 5°37′30″. A planet that stood in that segment at the moment of birth switches the Gate on in the chart. Each Gate belongs to one of the nine centers of the bodygraph — that center is where its theme shows itself.
The calculation is done twice: for the moment of birth (Personality, the black Gates — what a person notices in themselves) and for roughly three months before it, when the Sun was 88° earlier (Design, the red ones — what is seen more from the outside).
Shadow, gift and siddhi — three volumes of one theme
These three words come from Richard Rudd’s “Gene Keys” (2009): each of the 64 keys has a shadow — the distorted sound, a gift — the working one, and a siddhi — the highest. These aren’t three different states, but one energy at different volumes. The working rule is simple: if the gift has come, keep going; if you notice the shadow, take a pause. The “Gene Keys” are a separate system built on the same 64 hexagrams; in Ra Uru Hu’s classical Human Design these words don’t exist.
The six lines
Inside each Gate there are six lines, the six lines of the hexagram, 56′15″ of arc each. Which line is switched on depends on the planet’s exact degree, so lines need an exact birth time. The lines of the Sun and Earth add up to the Profile: 3/5 is the third line of the Personality Sun and the fifth of the Design Sun. The same Gate with different lines sounds different: 64 Gates times six lines make 384 shades.
In Ra Uru Hu’s book each line has two poles — exaltation and detriment, and most of them have a planet assigned. Which pole sounds in a person is decided in Human Design by the planets of their chart; on a Gate’s page both are given for each line.
Melancholy
For some of the Gates — mostly of the Individual circuit — a melancholy of their own is described: sadness with no outside cause, which for these Gates serves creativity rather than illness. Where it exists, the Gate’s page says how it shows up and what to do with it.
Channels — two halves
A Gate is half of a channel. If the other half is in the same chart, the channel is defined and the theme works constantly. If it isn’t, the Gate is “hanging”: the theme is switched on by people with the other Gate — next to them the channel completes itself, and that’s one of the reasons we are different with some people than with everyone else.
Programming partner
Opposite each Gate on the circle, 180° away, stands another — the opposite pole of the same theme. This pair is called programming partners: one can’t be read without the other, which is why a Gate’s page always has a link to its partner.
How to check the Gates on yourself
Take the Gate of your Personality Sun — the loudest in the chart. Read its shadow and gift and recall three occasions over the past year when this theme was at the center: work, a quarrel, a decision. If in at least two you recognize either the shadow or the gift — it’s a hit. If in two out of three or more you recognize neither one nor the other — the description isn’t about you, however beautiful it sounds. A hit proves little: the themes of the Gates are broad, while a miss is an honest negative result.