Sri Sadgurubhyoh Namah
The next four sutras in VBT (28 to 31) relate to kundalini dhyana. These four dhyana require that kundalini energy should be awakened and made to enter the sushumna channel to experience what these sutras are talking about. The way to awaken kundalini shakti needs to be learnt from a Spiritual Master and should be done under supervision.
There are total 12 energy centers called chakras in a human body, aligned along the spine and brain. They are,
a) Muladhara : Located at the base of spine. bija mantra 'Lam'.
b) Svadhishtana : Located behind genital organ. bija mantra 'Vam'
c) Manipura : Located behind naval. bija mantra 'Ram'
d) Anahata : Located in heart region. bija mantra 'Yam'
e) Vishudhdhi : Located in throat region. bija mantra 'Ham'
f) Ajna : Located in forehead. bija mantra 'Aum'
g) Lalana : Located between vishuddhi and ajna. bija mantra 'ham'
h) Nasikagra : Tip of nose. bija mantra 'so'
i) Manas : Lower forehead chakra. bija mantra 'Aum'
j) Soma : Above the ajna, near hairline. bija mantra 'Aum'
k) Bindu : The place where brahmins leave a tuft of hair. bija mantra 'Aum'
l) Sahasrara : Crown of head. bija mantra 'Aum'
The bhairavi shakti known as Parashakti is also known as kundalini shakti. It lies dormant at base of spine in muladhara chakra. When this energy is awakened due to the grace of Guru, it travels in sushumna through all the other chakras and merges with Shiva at sahasrara chakra.
I will try to explain the sutras 28 to 31 as best as I can.
1. VBT 28 :
Amoolaat kiranaabhasaam sookshmaat sookshmataraatmikaam,
chintayettaam dvishatkaante shaamyanteem bhairavodayah
translation :
Meditate on the energy, rising from root like the ray of sun, slowly becomming dimmer and dimmer, subtler and subtler as it goes up to twice six (12) and dissolves with experience of the manifestation of Bhairava consciousness.
My understanding :
You can visualize in your mind that the energy (shakti) is like the rays of sun, starting from muladhara, and going up along the spine, and travelling along the 12 chakras (twice six) and ending at sahasrara (also known as dvadashaanta end of 12, twice six). Your visualization at muladhara for the energy as rays of sun, is done with effort of mind and as you use your mind to travel this sun-rays spreading along the spine up, the visualization (effort of mind) becomes dimmer and dimmer and when your visualization reaches sahasrara (dvadashaanta, end of twelve), it dissolves there, and you experience Bhairava consciousness.
2. VBT 29 :
Udgachchanteem tadidroopam pratichakram kramaat kramam,
oordhvam mushtitrayam yaavat taavad ante mahodayaha
translation :
Meditate on kundalini moving upwards like lightenining through all chakras one by one to 'measuring three fists', until at last the great dawn takes place.
In earlier sutra it is said to meditate on the energy as rays of sun, like a slow gradual movement of light. Here in this sutra, the energy has to be meditated as 'lightening' , from muladhara to sahasrara (three fists = 12 fingers = twice six). You have to do this visualization, until atlast the great dawn of Bhairava consciousness happens.
3. VBT 30 :
Kramadvaadashakam samyag dvaadashaaksharabheditam,
sthoolasookshmaparasthityaa muktvaa muktvaantatah Shivaha
translation :
The twelve should be pierced successively with right understanding of twelve letters, thus getting liberated the gross, subtle, beyond one by one, and finally becomes Shiva.
Akshara means indestructible and also letters (sound, alphabet) of language. First there is the cosmic sound AUM. From that all the sounds of sanskrit language came and the manifest world came from those sounds. Each sound of sanskrit alphabet, is of a particular frequency. When we utter one alphabet of sanskrit, one part of our consciousness is activated. Each chakra is associated with a bija akshara. What it means is that , when you chant the bija akshara of that chakra, one part of our consciousness related to that chakra gets activated.
The bija mantra for each chakra is given above.
This sutra explains that , When there is inner understanding of each bija mantra, what is its effect on our consciousness, then that related chakra is pierced and understood. Once each chakra is pierced, The gross, subtle and beyond are liberated one by one, and finally consciousness becomes Shiva cosnciousness.
What is the practice to do : Daily chant the bija mantras of each chakra few times, bringing our awareness to the location of the chakra.
4. VBT 31 :
Tayaapooryaashu moordhaantam bhanktvaa bhrookshepasetunaa,
nirvikalpam manah kritvaa sarvordhve sarvagodgmah
translation :
Then, having filled the tip of moordha, and crossed the bridge between eyebrows, mind becomes free from thought patterns, and above all omnipresence rises.
My understanding :
When dharana is done at ajna chakra and above, the various thought patterns of mind becomes eliminated and a sense of omnipresence rises.