The rising sign in the natal chart is called Lagna or the Ascendant. It is actually a point in the zodiac, in the eastern horizon at a particular time when one living being or an entity (nation, party, business, association etc) comes into existence in the manifested world.
We can say that it is the time and space equation for an individual/ an entity which governs its entire existence.
The Ascendant governs the attitude, ideals, outlook, inherent nature of a person and all that which gives him a sense of individuality or identity. Consequently, the person behaves or reacts in a certain manner depending upon this internal makeup.
The moment we talk about existence in the material world, an identity or ” I ness” becomes necessary for all to exist individually; this ” I ness” is born from ego (ahamkara).
This “I ness” must have some attributes and a physical body to exist in the manifested world separately as different from others. Lagna is sum total of the entire “I ness” of a native or his complete real personality. It is the physical interface (body) via which a human being comes in contact with the external world and others. The Ascendant Lord is the intelligence of a human being that guides his existence in the manifested world.
There are various kinds of existences for a native depending upon the context we are taking under consideration. Hence there are various types of Ascendant used to judge different aspects.
There is existence at the spiritual level (Atma Karaka as Lagna), one at the physical level to physically interact with the external world (Ascendant in Rashi chart) and one at material level i.e. status, reputation and image in the society (Arudha Lagna). Existence with respect to mind or moon is called Chandra Lagna. There are other important categorizations like existence w.r.t wealth and sustenance (Hora Lagna), existence w.r.t power/authority one commands (Ghatika Lagna), existence w.r.t prosperity, wellbeing and blessings of the mother (Shri Lagna) etc.
The Ascendant is the reference frame for any individual living or nonliving entity from which all other concerned aspects are judged. The results of all the other houses should be favorable for the Ascendant under consideration. Hence Raj yoga is formed by the lord of quadrants and trines only because these houses are auspicious for the Ascendant.
Adhana Lagna (Conception): is the situation when the process of creation of life just begins. It commences the process of coming together of a mind and a soul and formation of a physical body.
The Ascendant is a trine (representing blessings of goddess Laxmi) as well as a quadrant, (representing efforts i.e. Lord Vishnu) that is why the rising sign becomes very auspicious and important.
All the divisional charts (Varga chakras) are calculated from the natal chart (janma kundali) only. As in natal chart, the Ascendant represents a native, so in all divisional charts, the Ascendant always represents the native in that scenario.
Introductory lecture in Hindi on Lagna, Arudha Lagna, Hora Lagna, Ghatika Lagna
हिन्दी में ज्योतिष ऑडियो लैसन: लग्न, आरूढ़ लग्न, होरा लग्न, घटिका लग्न और कुछ महत्वपूण बातें