(8) Saankhya Yog - As Gyaan Yog.

(9) Raaj Yog - In this Yog one tries to control his life air within the body.

(10) Mantra Yog - When people recite any specific Mantra many many times, it is called Mantra Yog. It may involve the softly spoken repetition of a prayer or Mantra for one's own meditation, or it may be the congregational singing of spiritually uplifting songs, prayers, or the sacred names of the Supreme Being. It all involves the same process, but in the Eastern tradition it is called Mantra Yog because it is the easy process of focusing our minds on the Supreme, which helps spiritualize our consciousness. Man means the mind, tra means deliverance. Therefore, a spiritual Mantra is the pure sound vibration for delivering the mind from material to spiritual consciousness. This is the goal of any spiritual path. Although all spiritual traditions have their own prayers or Mantra, the Vaidik Mantra are especially powerful and effective in uniting us with the spiritual realm.

To attain Moksh, the three paths - Bhakti Yog (the path of Devotion), Karm Yog (path of dedicated action) and Gyaan Yog (the pursuit of knowledge) are not mutually exclusive. To each one of them, the other two are complimentary. Unless the quantity and quality of thoughts are modified ,the direction of thought can not be changed. All the three paths are to be practiced in synthesis. Each one of us have to discover for ourselves our main path and also realize that the other two can not be totally eliminated. Once success is attained in controlling the mind by following the paths as above, success in meditation will be assured. And it is through meditation alone Moksh or Self-realization can be attained.

(3) Yog in Indian Astrology
In Indian astrology, Yog is a part of Panchaang. There are 26 Yog in number and come through out the month in a specific sequence. They are like Nakshatra which also come throughout the month in a specific sequence. Their names are - (1) Shubh, (2) Shukla, (3) Brahm, (4) Aindra, (5) Vaidhritti, (6) Vishkumbh, (7) Preeti, (8) Aayushmaan, (9) Saubhaagya, (10) Shobhanaa, (11) Atigand, (12) Sukarmaa, (13) Dhriti, (14) Shool, (15) Gand, (16) Vriddhi, (17) Dhruv, (18) Vyaghat, (19) Vajra, (20 Siddhi, (21) Vyatipaat, (22) Vareeyaan, (23) Prigh, (24) Shiv, (25) Siddh. Thus one Yog stays for just a little over a day, that is why they are called Day Yog

Conjunction of Planets
Lucky or unlucky conjunctions of Planets or stars are also called Yog - they are 10 in number --
(1) Vava, (2) Valav, (3) Kaulav, (4) Taitil, (5) Vanij, (6) Vishti, (7) Shakuni, (8) Chatushpad, (9) Kintughn, and (10) Naago-yog

Conjunctions of Several others
There are some other types of Yog - means combinations, in Indian astrology. This combination may be of anything - Nakshatra + Day; Day + eclipse; Nakshatra + Sankraanti etc etc. For example -

(1) Choodaamani Yog - If solar eclipse is on Sunday, or lunar eclipse is on Monday, it is called Choodaamani Yog. Bathing and donating during that time give eternal fruits.
(2) Guru Pushya Yog - Guru Pushya Yog was on 8th of August, 2002. This Yog is highly auspicious to perform any new thing and any Saadhanaa irrespective of the Muhoort prescribed; for it can be started from the time of a Guru Pushya. It is supposed to be a thousand times more powerful. What is so special of this time is that Jupiter is passing through it's maximum exaltation point in Cancer Sign which happens only once in 12 years (as Jupiter's cycle is of 12 years), so apart from other things, till 15 September (but even till June 2003) it was highly auspicious time to appease Jupiter. And Guru Pushya Yog was also a Gaj Kesaree Yog that time.

Hath Yog

Ashtaang Yog
Read about it what Agni Puraan says about it. According to [Naarad Puraan, 1/13] A Yogee destroys his A-Gyaan through Yog. Yog is completed through eight parts. They are - (1) Yam, (2) Niyam, (3) Aasan, (4) Praanaayaam, (5) Pratyaahaar, (6) Dhaaranaa, (7) Dhyaan, and (8) Samaadhi. Now I tell you their characteristics.

1 - Yam - 
(1) Ahinsaa (non-violence), (2) Satya (truth), (3) A-Steya (not stealing or robbing), (4) Brahmcharya (abstinence), (5) A-Parigraha (not collecting anything), (6) A-Krodh (not being angry), and (7) An-Sooyaa (not feeling jealous with others' progress) - are the seven characteristics of Yam. Not to pain anybody in any way is called A-Hinsaa. Whatever truth is spoken taking Dharm and A-Dharm into consideration, is called Satya (truth). Stealing or taking anybody's wealth forcefully is called "Steya". Opposite to this is called A-Steya. Abstinence is known as Brahmcharya. Not to collect anything even for emergency is said as A-Parigraha. Who speaks harshly showing his highness to others, the same cruel behavior is called Krodh (anger). The opposite of Krodh is A-Krodh - means showing politeness to everybody. When one feels jealous seeing others' progress in anything, it is called Asooyaa; and not feeling Asooyaa is called An-Sooyaa. They are called Yam.

[Five Yam to practice Yog - (1) Brahmcharya - abstinence, (2) Ahinsaa - non-violence, (3) Satya - truth, (4) A-Steya - not to steal or rob, and (5) A-Parigraha - not collecting anything even for emergency]

[According to Bhaagvat Puraan, 11/16, there are 12 types of Yam - (1) Ahinsaa, (2) Satya, (3) A-Steya, (4) Asang - not being attached to worldly pleasures, (5) Lajjaa - feeling shame, (6) A-Parigraha, (7) Being Aastik - theist, (8) Brahmcharya, (9) Maun - not speaking or being quiet, (10) Stability, (11) Forgiveness, and (12) Being Fearless.]

2 - Niyam - 
Now you listen to about Niyam. (1) Tap (penance), (2) Swaadhyaaya (self-study), (3) Santosh (contentment), (4) Shauch (cleanliness), (5) Vishnu's worship, and (6) doing Sandhyaa etc are called Niyam. When anyone weakens his body by doing Chaandraayan etc Vrat (fasts), it is called Tap. This is a good means of Yog. Jap, study, and thinking about Omkaar, Upanishad, 12-letter Mantra, 8-letter Mantra, or Tat Twam Asi etc are called Swaadhyaaya. This is also a good means of Yog. Whoever fool abandons this Swaadhyaaya his Yog doesn't get Siddh (completed), but even without Yog, a man's sins are destroyed only by self-study. Self-study pleases Isht Devtaa. Jap is said to be of three types - Vaachik, Upaanshu and Maanas - the last one is the best. When a Mantra is pronounced methodically and clearly, it is called Vaachik Jap. It gives the fruit of all Yagya. When a Mantra is pronounced in a lower voice separated one word from another, is called Upaanshu Jap. This is twice the more beneficial than the first one. When a Mantra is pronounced in heart thinking about the words and their meanings, it is called Maanas Jap. This Jap completes the Yog. Who pray their Isht Devtaa by Jap, their Isht Devtaa are always pleased with them. That is why who is busy in Swaadhyaaya he can fulfill his all wishes.

Being contented with whatever is available is called Santosh (contentment). A discontented man is never happy anywhere. Shauch (cleanliness) is of two types - external and internal. Cleaning the body from outside is called external cleaning and purifying ones thought and mind is called internal cleaning. Who are internally clean and they do Yagya, those Yagya are useless. Whose heart and mind are clean and if they behave according to Dharm, then its result is immortal and makes one happy. When a man develops strong Bhakti by doing constant Poojaa; by prayer by heart, speech and action; and by hearing His stories, the same is being told as Vishnu's Poojaa. Sandhyaa is also to be done at both times.

Thus I told you about Yam and Niyam, if somebody's heart and mind has become clean by these processes is considered to attain Moksh, so one should practice Aasan after stabilizing one's mind by Yam and Niyam.

[According to Bhaagvat Puraan, 11/16  Niyam are also 12 - (1) Shauch - cleanliness of inside and outside of the body, (2) Jap, (3) Tap, (4) Havan, (5) Shraddhaa, (6) Hospitality, (7) My Worship, (8) Teerth Yaatraa (traveling in holy places or pilgrimage), (9) To do good to others, (10) Santosh - contentment; and (11) Service to Guru. These are useful for both Sa-Kaam and Nish-Kaam Saadhak.]

3 - Aasan - 
Although there are 84 Aasan but these 30 Aasan are recommendable for meditation. (1) Padm Aasan, (2) Swastik Aasan, (3) Peeth Aasan, (4) Sinh Aasan, (5) Kukkut Aasan, (6) Kunjar Aasan, (7) Koorm Aasan, (8) Vajra Aasan, (9) Varaah Aasan, (10) Mrig Aasan, (11) Chailik Aasan, (12) Kraunch Aasan, (13) Naalik Aasan, (14) Sarvatobhadra Aasan, (15) Vrishabh Aasan, (16) Naag Aasan, (17) Matsya Aasan, (18) Vyaaghra Asan, (19) Ardhchandra Aasan, (20) Dandvaat Aasan, (21) Shail Aasan, (22) Khang Aasan, (23) Mudgar Aasan, (24) Makar Aasan, (25) Tripath Aasan, (26) Kaashth Aasan, (27) Sthaanu Aasan, (28) Vaikarnik Aasan, (29) Bhaum Aasan, and (30) Veer Aasan - all these 30 Aasan are good to do Yog. A Saadhak should use any one of these Aasan and practice Praanaayaam.

4 - Praanaayaam - 
Where there is no crowd, nor there is any noise, one should this practice in such a place. Whatever air is inside our body that is called Praan; and to control this Praan is called Aayaam. There are two types of Praanaayaam - A-Garbh and Sa-Garbh. The latter one is better. Whatever Praanaayaam is done without Jap and meditation that is called A-Garbh; and whatever Praanaayaam is done with Jap and meditation, that is called Sa-Garbh. These two types of Praanaayaam are also of four types - Rechak, Poorak, Kumbhak, and Shoonyak.

Jeev's right nerve is called Pingalaa whose Devtaa is Soorya. This is called Pitri Yoni. In the same way the Jeev's left nerve is Idaa whose Devtaa is Chandra Dev. This is called Dev Yoni also. And in the middle of these there is Sushumnaa nerve. This is very subtle and very hidden. Its Devtaa is Brahmaa Jee. One should exhale air from his left nostril, and inhale from right nostril. Exhaling process is called Rechak, and inhaling process is called Poorak. When one fills the air in his body and doesn't release it, sits like a filled pitcher, it is called Kumbhak. When the air is neither inhaled, nor it is exhaled and one sits just like that, it is called Shoonyak. One should control this Praan gradually otherwise serious diseases can attack. 

5 - Pratyaahaar - 
To control one's Indriyaan (senses) from all pleasures of the world is called Pratyaahaar. Who meditates without controlling his Indriyaan, his meditation is useless.

6 - Dhaaranaa -
A man sees whatever things, understands it as his own soul; and keeps his controlled Indriyaan in his soul is called Dhaaranaa. Control one's Indriyaan through Pratyaahaar and keep them in his soul and then meditate on Hari imagining His beautiful image.

7 - Dhyaan -
When one's mind and heart become one with the image he is meditating upon, is called Dhyaan. Even one hour Dhyaan is enough to attain Moksh. Dhyaan destroys sins, Dhyaan pleases Vishnu and Dhyaan fulfills all wishes. Any image of Vishnu could be used for meditation.

8 - Samaadhi - 
When one meditates, gradually one comes one with the image he is meditating upon. This stage, of becoming one with the image, and becoming stable filled with joy is called Samaadhi. Hey Naarad Jee, A Yogee neither sees, nor smells, nor touches, nor speaks anything. In that state, he sees only attributeless, pure, clear Aatmaa. Paramaatmaa is the subtlest of the subtlest one and the greatest of the greatest one. Existed from Akaar to Hakaar (from A to H - Hindi alphabet), in every letter in different forms, He is said Shabd-Brahm.

Now I tell you about another Dhyaan. Bhagavaan exists in Pranav (Aum). One should imagine Him like this. In Aum (see its image) Akaar is the form of Brahmaa Jee, Ukaar is Vishnu's form and Makaar is Rudra's form, and the mark above it represents Paramaatmaa. Who do Jap of Pranav they become free from all kinds of sins.

System of Philosophy
(From "a New History of India". by Stanley Wolpert. 2004. p. 96.)

Yog was only one of six schools of classical Hind Philosophy that emerged in this era and that continued to be studied throughout India to this day. The Saankhya school, closely related to Yog may also antedate the Aarya's conquest, though its oldest surviving text, Ishvar Krishna's "Saankhya Verses", dates only to about the 2nd century AD. This philosophy analyzes the world as consisting of 25 basic principles, 24 of which are matter (Prakriti or nature) and the 25th one being "Spirit", or "Self" (Purush). There is no Divine creator in this system. All matter is eternal, uncaused, but basically three-fold in its qualities, or strands or attributes (Gun) - Sat (truthful), Rajas (passionate), and Tamas (dark). Whichever of these qualities dominates will determine the "nature" of things and people, virtuous or noble, strong and bright, or inert, dull, mean, cruel, and so forth. 

The 24 forms of matter evolve from "Prakriti", 
Prakriti brings forth Buddhi (intelligence), 
Buddhi gives birth to Ahankaar (ego-sense), 
Ahankaar gives birth to Manas (mind), 
from which the five senses emerge [seeing, hearing, taste, smell, touch] and 
from the senses emerge five sense organs [eyes, ears, tongue, nose, sense]
the five sense organs give rise to action organs - [hands, feet, reproduction, excretion] and finally
emerge he five gross elements - [ether, air, light, water, earth].

Purush stands alone, however, there are an infinite number of such "men", all equal, each of which unites with the feminine gender "Prakriti". The ultimate salvation of Purush lies in his recognition of separateness and distinction from Prakriti, allowing the Spirit or soul to cease suffering and attain freedom.

Four Other Philosophies
The four other schools of classical Hindu Darshan (philosophies) are generally also coupled - Nyaaya with Vaisheshikaa; and Poorv-Meemaansaa with Vedaant.

Nyaaya means analysis and it is the Hindu system of logic which teaches salvation through knowledge of some 16 categories of reasoning and analysis, including syllogism, debate, refutations, disputations and argument of every sort. This Nyaaya system is more elaborate than the Greek, its typical 5-part example being - (1) the hill is on fire, (2) because it is smoky, (3) whatever is smoky is on fire, as in kitchen, (4) so with the hill, (5) therefore, the hill is on fire. Not only do Hindu logicians insist on a middle example, they also caution against no fewer than five kinds of fallacious middles, making Nyaaya the world's most intricate and elaborate system of logical analysis.

The Vaisheshikaa (individual characteristics) school of Hindoo philosophy is sometimes called India's "atomic" system, for its basic premise is the unique character of each element of nature. The material universe emerges from the molecular interaction of the atoms that make up earth, water, air, and fire. There are, however, There are, however, non-atomic Dravya ("substances") as well, such as soul and mind, or time and space, to help explain whatever the atomic theory may leave inexplicable. Salvation in this school, is achieved through perfect knowledge, following which the "self" is released from matter and rebirth.