Vastu is an ancient Indian science that deals with the rules of placement and internal planning of residential and administrative buildings so that these buildings and apartments were in harmony with their natural environment.
Different sources name this science variously: Vastu-shastra, Vastu-vidya, Vaastu or simply Vastu.

The science takes its name from the Sanskrit radical “VAS” which means “to be” or “to live”. The Earth is the primary substance or Vastu; the vitality of the Earth is also Vastu. All the material world, everything situated on the surface of the Earth, in the space, the surface itself and every confined space is called Vaastu. Thus, Vastu is the living space, particularly the dwelling or the confined territory around it. In this context VASTU and VAASTU have one and the same meaning, but as is common in the modern Indian literature as well, the science is called simply Vastu with the single “a”.

The Vastu-shastra is based on the harmony of the universe expressed by the lunar, the solar and the temporal influence on the consciousness and on the physiology of a human being. For this reason this science is closely bound up with the Vedic Astrology and with the Ayurveda.
All the Vastu recommendations are meant to guide the man in obtaining the perfection in life, that is to perceive the Divine and his own nature and methods of the mutual relationship.
There are the principles of the energy of the ambient space, the subtle, invisible principles penetrating through the whole universe and according to these principles all the objects are related with each other on the fine structure level. Consequently, if your home or office ambience is in contradiction with these principles such contradiction may lead to various problems: decline of health, conflicts, loss in business.

The science of Vastu considers firstly the energies radiated by the four corners of the Earth: the North, the East, the South and the West; it is recognized that the energies of different corners of the Earth have a different effect on the human organism.
Each direction takes its octant and has its own lord-protector. The project of a house and its surrounding area should consider the consequence of each of their zones to the characteristics of their own lord-protectors. Then the Gods pacified will ensure the even tenor of life and prosperity. This is the main principle of the Vastu.

Besides, according to the Vastu whole the world comprises five basic elements: Earth, water, fire, air and quintessence. These elements correspond to their own directions. The whole point of it is how and in what ratio these elements should be balanced in order to be in harmony with the nature.

Being an inherent part of the vedic culture the Vastu considers amongst the other factors the impact of the Sun, the Moon and their exposure time. The Indian Rishis recommended to take into account the position of the sun during the day-time while designing a house. The rays of the Sun should lighten each room in a particular period of time because the activity of the human organism depends of the time of day. Different parts of a house should be in harmony with the migrating solar light and correspond the everyday life of people.
Each spatial direction and the illumination of one or another part of the house has an effect on the human activities. That’s why some or other occupation should be exercised in a corresponding room taking into consideration the penetration of the sunbeams beginning with the sunrise on the East and ending with the sunset on the West. The first morning hours for example are the best time for practicing yoga, meditating and studying.

The knowledge of personal horoscope of an individual and Vastu Vidya can help to determine the fortunate moment to start the housebuilding, to choose the most preferable place for the entrance, to specify the day for the groundbreaking and moving to the house and to decide on the alteration of a house or an apartment to live there in harmony and joy.