Rashi Lagna is the sign rising on the eastern horizon at the time of birth. It is the first bhava in the horoscope. The first house/bhava in horoscope in astrology is known as Rashi Lagna/ Ascendant. In the image the lagna is Gemini. The laganesh is Mercury. The Lagana is denoted by sign As. The chandra lagana is Where moon is placed(Virgo) in the image.
The ruler of the first bhava/ Lagna is known as Lagnesha or Lagna lord/ ascendant lord. The Lagna and the lagnesha together help us decide the physical body, physical attributes, social and economical natural tendencies and external behaviour patterns of the native. The graha/ planet occupying the Lagna will help us decide the social profile of the native along with the lagnesha. The conjunctions of planets and aspects will modify the outcome. Lagnesha shows social patterns, Chandra lagna shows emotional patterns. If the chandra/ moon is placed in the first house then the rashi Lagana and the chandra Lagna are the same.
The Nakshatra of the ascendant will also add the flavor to the physical body and social behavior.
The placement of the lagnesha in the horoscope of a native will show the focus area of life. For example, if the Lagna is Leo , then in addition to significance of the sign Leo the position of the Sun in the horoscope will give us the clue about the life of the native.
The placement of lagnesha in the Trik houses is less struggles, in upachaya houses 3,6,10,11 will give better life as life progresses, the Placement of lagnesha in 6,8,12 will definitely add extra struggles to some areas of life.
