How many main directions are there in Vastu?
Ten, not four: the four main directions, the four corner directions (vidisha), and the upward (urdhva) and downward (adho) directions. Each has its own dikpal, and energy reaches the rest from above and below.
Related questions
A client's location shows coordinates. What do I do with them?
Copy them and paste them into the Google Earth search bar, which takes you to the place. Then draw a straight line along a wall of the building to get the degree. A degree taken from the centre is wrong; the centre only tells you which direction a room is in.
About 11 or 12 of the 45 devtas are asuras. Whose energy should be increased and whose kept low to stay balanced?
This was to be explained in detail later, as there is a big confusion about it. Asura devtas are also needed: the day there are no asuras in your house, your work will not run, so the aim is balance, not removing them.
Apart from gridding the house, should the kitchen be gridded separately?
Yes. Interior vastu means zoning each room separately with its own grid and then designing its interior accordingly.
Are three doors in a straight row inauspicious?
They can be either. In the South and West, from where negative energy comes, three doors in a row on padas where doors should not be are inauspicious. In the North and East they are auspicious: temples, all built facing North or East, have three or five doors in a row, as do royal palaces, so the blanket belief that they are bad is a myth.
At what degree do the corner directions (vidisha) fall?
North-East, South-East, South-West and North-West fall exactly 45 degrees from the main directions. Where they fall in your own flat becomes clear once you do the zoning.
At what time does the West direction show its greatest energy?
After sunset. Its power is felt from sandhya kaal onward and increases as the night advances, which is why people do sadhana at night and worship Lakshmi at night for wealth.