The Shodashamsha chart, D-16, is the ninth of the sixteen divisional charts, formed by dividing each sign into sixteen parts. It signifies vehicles, comforts, and luxuries, the conveyances a person owns and the material pleasures and ease of life, together with the happiness or trouble these bring. It is also called the Kalamsha. An astrologer consults the D-16 for questions of moveable property, conveyances, and the enjoyment of comfort. 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 mathematical technique for drawing focused readings from the same planetary positions recorded at the moment of birth.
The finer vargas from the D-16 onward receive comparatively little elaboration in the surviving classical sources compared with the detailed, named rules given for the Hora, Drekkana, Saptamsha, Navamsha, Dashamsha and Dwadashamsha, and modern Jyotisha software packages do not always agree with one another on the exact starting-point convention for these later charts, a genuine and acknowledged point of technical disagreement among contemporary practitioners rather than a settled classical rule. The Shodashamsha's association with vehicles has broadened in modern practice, given the sign's original agrarian and animal-drawn conveyances, to cover motor vehicles and other mechanised transport, an extension of the classical category rather than a change to the chart's underlying construction.