Drekkana or D3 chart is one of the important divisional charts in vedic astrology. Each sign of your lagna chart is dividied into 3 equal parts of 10 degree each. There are different types of drekkana like somnath drekkan or jagannath drekkana, parashari drekkan etc. It is representative of 3rd house of your horoscope. It can be said as microscopic view of the area of life governing siblings, elder and younger. It can also be seen for courage and communication. In Prashna shastra it is used to identify thief. Different drekkanas are attirbuted some looks and significations which helps in identifying thief.
Parashari Drekkana Planets between 0-10 degrees remain in same sign in drekkana chart as in lagna chart. Planets in 10-20 degrees go in 5th sign from their own sign in D3 chart. And finally planets between 20-30 degrees go to 9th sign from their sign in dreshkona chart.

To find the nature of a person – Three drekkanas are attributed 3 sages, Narad, Agastya and Durvasa. Planet is said to be in narada drekkana if it is placed in movable sign in D3 chart. Similarly planets placed in fixed signs in D3 are of Agastya and in dual are of durvasa.
Each sage has specific characteristic: Narada – Likes travelling, messenger, devotee, back biter
Agastya – Strong willed, ready to face any challenge, fixed in nature, does not like to wander
Durvasa – Short tempered, ego, traditional, can cause destruction

First house in D3 chart is seen for promise of coborns and their general well being.
Second house is seen for gain of wealth from coborn
Third house is seen for courage, immediate younger sibling
Fourth seen for happiness from and to coborn
Fifth house in D3 chart is seen for second younger sibling
6th house is seen for karma
7th house is seen for desires
Eighth is seen for longevity, obstacles. It is also khara drekkana
Ninth house is seen for second elder coborn
tenth is seen for action undertaken to achieve goals
11th is seen for fullfilment of desire, immediate elder sibling
Twelfth is seen for losses to or due to coborns, seperration
Khara Drekkana
22nd drekshkona is known as khara and its lord is known as kharesh. The 8th house of the D3 chart is the 22nd dreshkona. Lord of this house is kharesh. It indicates physical harm to the native. Kharesh from the moon indicates mental troubles and so on. In vedic astrology D3 chart has multiple usage from finding events related to siblings to diseases in body parts.