The Trimshamsha chart, D-30, is the thirteenth of the sixteen divisional charts, formed by dividing each sign into thirty parts. It signifies misfortunes, evils, and adversity, the troubles, illnesses, and moral trials a person may face, and their sources. Unlike most vargas its thirty divisions are assigned to the five non-luminous planets in an unequal scheme, and it is read especially for questions of character, hidden faults, and affliction. An astrologer consults the D-30 for the darker undercurrents of a nativity. The chart is one of the shodashavarga, the harmonic subdivisions through which jyotisha magnifies each department of a single nativity. These are the interpretive conventions of the tradition; the divisional charts are a technique for drawing focused readings from the birth longitudes.
The thirty divisions are not equal: Mars, Saturn, Jupiter, Mercury and Venus, the five non-luminous classical planets, are given five, five, eight, seven and five degrees respectively within an odd sign, in that order starting from zero degrees, while an even sign reverses both the order and the direction, so that Venus rules the first span and Mars the last. Because the assignment always uses this same fixed five-planet sequence regardless of which sign is being divided, and never involves the Sun or Moon at all, the D-30 is built on a wholly different logic from the equal, sign-derived divisions of the Hora through Dwadashamsha, which is part of why the tradition treats it as reading something categorically different, misfortune and affliction, rather than another department of ordinary life.