The Channel of Rhythm (5-15) is one of the thirty-six channels of the Human Design bodygraph, a system originated in 1987 by Ra Uru Hu and described here as a modern esoteric framework rather than an ancient tradition. A channel is a defined pathway joining the Sacral centre and the G/Identity centre, and it is completed by two gates: Gate 5 ("Natural Rhythms") and Gate 15 ("Embracing Extremes"), whose numbers come from the King Wen sequence of the I Ching. The channel idea and its Tree-of-Life-style pathways, the gates' I Ching numbering, and the centres' chakra roots were combined for the first time in the 1980s; the channel is part of that composite, presented as the system's own model, not as verified fact.
In the system's own account, the Sacral centre carries life force and work energy, read as the body's own generator and its yes or no gut response, and the G/Identity centre carries a sense of self, direction and love, read as the seat of identity in the model; the channel is read as a direct circuit between those two functions whenever both gates are defined in the same chart.
The same two numbers appear elsewhere in this atlas as Gene Keys 5 and 15, Richard Rudd's later, contemplative reading of the identical hexagram pair. Gene Key 5 runs from the Shadow of Impatience through the Gift of Patience to the Siddhi of Timelessness; Gene Key 15 runs from Dullness through Magnetism to Florescence. Rudd's system drops the bodygraph and its channels entirely, so this particular pairing is a Human Design structure only, with no equivalent in his contemplative method.