Sikhism (/ˈsɪkɨzəm/; Punjabi: ਸਿੱਖੀ, sikkhī, Punjabi pronunciation: [ˈsɪkːʰiː]) is a panentheistic religion founded during the 15th century in the Punjab region of the Indian subcontinent, by Guru Nanak and continued to progress through the ten successive Sikh gurus (the eleventh and last guru being the holy scripture Guru Granth Sahib. The Guru Granth Sahib is a collection of the Sikh Gurus' writings that was compiled by the 5th Sikh Guru). It is the fifth-largest organized religion in the world, with approximately 30 million adherents. Punjab, India is the only state in the world with a majority Sikh population.

Adherents of Sikhism are known as Sikhs (students or disciples). According to Devinder Singh Chahal, "The word 'Sikhi' (commonly known as Gurmat) gave rise to the modern anglicized word 'Sikhism' for the modern world." Gurmat means literally 'wisdom of the Guru' in contrast to Manmat, or self-willed impulses.

Philosophy and Teachings

The origins of Sikhism lies in the teachings of Guru Nanak and his successors. The essence of Sikh teaching is summed up by Guru Nanak in these words: "Realization of Truth is higher than all else. Higher still is truthful living". Sikh teaching emphasizes the principle of equality of all humans and rejects discrimination on the basis of caste, creed, and gender. Sikh principles encourage living life as a householder.

Sikhism is a Panentheistic (in some respects) and a revealed religion. In Sikhism, the concept of "God" is Vāhigurū—is shapeless, timeless, and sightless (i.e., unable to be seen with the physical eye): niraṅkār, akaal, and alakh. The beginning of the first composition of Sikh scripture is the figure "1"—signifying the universality of "God". It states that "God" is omnipresent and infinite with power over everything, and is signified by the term Ik Onkar. Sikhs believe that before creation, all that existed was "God" and "God's" hukam (will or order). When God willed, the entire cosmos was created. From these beginnings, God nurtured "enticement and attachment" to māyā, or the human perception of reality.

The all pervading spirit – the concept of "God" in Sikhism
The concept of "god" is different in Sikhism than that of other religions. It is known as "Ik Onkar" or "one constant" or the all pervading spirit (which is taken to mean god). It is found in the Gurmukhi script This "spirit" has no gender in Sikhism (though translations may present it as masculine); it is also "Akaal Purkh" (beyond time and space) and "Nirankar" (without form). In addition, Nanak wrote that there are many worlds on which it has created life. Nanak further states that the understanding of "Akaal" is beyond human beings, but at the same time not wholly unknowable. "Akaal" is omnipresent (sarav viāpak) in all creation and visible everywhere to the spiritually awakened. Nanak stressed that god must be seen from "the inward eye", or the "heart", of a human being: devotees must meditate to progress towards enlightenment of heavenly life. Guru Nanak emphasized the revelation through meditation, as its rigorous application permits the existence of communication between god and human beings. The Mool Mantar, the opening line of the Guru Granth Sahib and each subsequential Raga:

    Gurmukhi: ੴ ਸਤਿ ਨਾਮੁ ਕਰਤਾ ਪੁਰਖੁ ਨਿਰਭਉ ਨਿਰਵੈਰੁ ਅਕਾਲ ਮੂਰਤਿ ਅਜੂਨੀ ਸੈਭੰ ਗੁਰ ਪ੍ਰਸਾਦਿ॥
    Transliteration: ikk ōankār sat(i)-nām(u) karatā purakh(u) nirabha'u niravair(u) akāl(a) mūrat(i) ajūnī saibhan gur(a) prasād(i).
    English: "There is but one all pervading spirit, and truth is its name! It exists in all creation; it does not fear; it does not hate; it is timeless and universal and self-existent, You will come to know it through seeking knowledge and learning!"

Liberation
Guru Nanak's teachings are founded not on a final destination of heaven or hell but on a spiritual union with the Akal which results in salvation or Jivanmukta, Guru Gobind Singh makes it clear that human birth is obtained with great fortune, therefore one needs to be able to make the most of this life. There has been some confusion among scholars, interpreting the pertinent religious texts as evidence that Sikhs believe in reincarnation and karma as the same as Hinduism and Buddhism when such is not the case. In Sikhism karma "is modified by the concept of God's grace" (nadar, mehar, kirpa, karam etc.). Guru Nanak states "The body takes birth because of karma, but salvation is attained through grace". To get closer to God: Sikhs avoid the evils of Maya, keep the everlasting truth in mind, practice Shabad Kirtan, meditate on Naam, and serve humanity. Sikhs believe that being in the company of the Satsang or Sadh Sangat is one of the key ways to achieve liberation from the cycles of reincarnation.

The Timeless Truth
According to Nanak the supreme purpose of human life is to reconnect with Akal (The Timeless One), however, egotism is the biggest barrier in doing this. Using the Guru's teaching remembrance of nām (the divine Word or the Name of the Lord) leads to the end of egotism. Guru Nanak designated the word 'guru' (meaning teacher) to mean the voice of "the spirit": the source of knowledge and the guide to salvation. As Ik Onkar is universally immanent, guru is indistinguishable from "Akal" and are one and the same. One connects with guru only with accumulation of selfless search of truth. Ultimately the seeker realizes that it is the consciousness within the body which is seeker/follower and the Word is the true guru. The human body is just a means to achieve the reunion with Truth. Once truth starts to shine in a person's heart, the essence of current and past holy books of all religions is understood by the person.

Singing and Music
Sikhs refer to the hymns of the Gurus as Gurbani (The Guru's word). Shabad Kirtan is the singing of Gurbani. The entire Guru Granth Sahib is written in a form of poetry and rhyme. Guru Nanak started the Shabad Kirtan tradition and taught that listening to kirtan is a powerful way to achieve tranquility while meditating; Singing of the glories of the Supreme Timeless One (God) with devotion is the most effective way to come in communion with the Supreme Timeless One. The three morning prayers for Sikhs consist of Japji Sahib, Jaap Sahib and Tav-Prasad Savaiye. Baptized Sikhs rise early and meditate and then recite all the Five Banis of Nitnem before breakfast.

Ten Gurus and Authority
The term guru comes from the Sanskrit gurū, meaning teacher, guide, or mentor. The traditions and philosophy of Sikhism were established by ten specific gurus from 1469 to 1708. Each guru added to and reinforced the message taught by the previous, resulting in the creation of the Sikh religion. Guru Nanak was the first guru and appointed a disciple as successor. Guru Gobind Singh was the final guru in human form. Before his death, Guru Gobind Singh decreed that the Gurū Granth Sāhib would be the final and perpetual guru of the Sikhs. Guru Angad succeeded Guru Nanak. Later, an important phase in the development of Sikhism came with the third successor, Guru Amar Das. Guru Nanak's teachings emphasised the pursuit of salvation; Guru Amar Das began building a cohesive community of followers with initiatives such as sanctioning distinctive ceremonies for birth, marriage, and death. Amar Das also established the manji (comparable to a diocese) system of clerical supervision.

Guru Amar Das's successor and son-in-law Guru Ram Das founded the city of Amritsar, which is home of the Harimandir Sahib and regarded widely as the holiest city for all Sikhs. Guru Arjan was captured by Mughal authorities who were suspicious and hostile to the religious order he was developing. His persecution and death inspired his successors to promote a military and political organization of Sikh communities to defend themselves against the attacks of Mughal forces.

The Sikh gurus established a mechanism which allowed the Sikh religion to react as a community to changing circumstances. The sixth guru, Guru Hargobind, was responsible for the creation of the concept of Akal Takht (throne of the timeless one), which serves as the supreme decision-making centre of Sikhism and sits opposite the Harmandir Sahib. The Sarbat Ḵẖālsā (a representative portion of the Khalsa Panth) historically gathers at the Akal Takht on special festivals such as Vaisakhi or Hola Mohalla and when there is a need to discuss matters that affect the entire Sikh nation. A gurmatā (literally, guru's intention) is an order passed by the Sarbat Ḵẖālsā in the presence of the Gurū Granth Sāhib. A gurmatā may only be passed on a subject that affects the fundamental principles of Sikh religion; it is binding upon all Sikhs. The term hukamnāmā (literally, edict or royal order) is often used interchangeably with the term gurmatā. However, a hukamnāmā formally refers to a hymn from the Gurū Granth Sāhib which is a given order to Sikhs.

Scripture

Adi Granth
The Ādi Granth was compiled primarily by Bhai Gurdas under the supervision of Guru Arjan between the years 1603 and 1604. It is written in the Gurmukhī script, which is a descendant of the Laṇḍā script used in the Punjab at that time. The Gurmukhī script was standardised by Guru Angad, the second guru of the Sikhs, for use in the Sikh scriptures and is thought to have been influenced by the Śāradā and Devanāgarī scripts. An authoritative scripture was created to protect the integrity of hymns and teachings of the Sikh gurus and fifteen bhagats. These fifteen bhagats are Namdev, Ravidas, Jaidev, Trilocan, Beni, Ramanand, Sainu, Dhanna, Sadhna, Pipa, Sur, Bhikhan, Paramanand, Farid, and Kabir. At the time, Arjan Sahib tried to prevent undue influence from the followers of Prithi Chand, the guru's older brother and rival.

Guru Granth Sahib
The final version of the Gurū Granth Sāhib was compiled by Guru Gobind Singh in 1678. It consists of the original Ādi Granth with the addition of Guru Tegh Bahadur's hymns. The Guru Granth Sahib is considered the Eleventh and final spiritual authority of the Sikhs.
    Punjabi: ਸੱਬ ਸਿੱਖਣ ਕੋ ਹੁਕਮ ਹੈ ਗੁਰੂ ਮਾਨਯੋ ਗ੍ਰੰਥ ।
    Transliteration: Sabb sikkhaṇ kō hukam hai gurū mānyō granth.
    English: All Sikhs are commanded to take the Granth as Guru.

It contains compositions by the first five Gurus, Guru Teg Bahadur and just one śalōk (couplet) from Guru Gobind Singh. It also contains the traditions and teachings of sants (saints) such as Kabir, Namdev, Ravidas, and Sheikh Farid along with several others.

Dasam Granth
The Dasam Granth is a scripture of Sikhs which contains texts attributed to the Tenth Guru. The Dasam Granth holds a significance of great amount for Sikhs, however it does not have the same authority as Adi Granth. Some compositions of the Dasam Granth like Jaap Sahib, (Amrit Savaiye), and Benti Chaupai are part of the daily prayers/lessons (Nitnem) of/for Sikhs.
The authenticity of the Dasam Granth is amongst the most debated topics within Sikhism.

Janamsakhis
The Janamsākhīs (literally birth stories), are writings which profess to be biographies of Nanak. Although not scripture in the strictest sense, they provide an interesting look at Nanak's life and the early start of Sikhism. There are several—often contradictory and sometimes unreliable—Janamsākhīs and they are not held in the same regard as other sources of scriptural knowledge.

Observances

Observant Sikhs adhere to long-standing practices and traditions to strengthen and express their faith. The daily recitation from memory of specific passages from the Gurū Granth Sāhib, especially the Japu (or Japjī, literally chant) hymns is recommended immediately after rising and bathing. Family customs include both reading passages from the scripture and attending the gurdwara (also gurduārā, meaning the doorway to God; sometimes transliterated as gurudwara). There are many gurdwaras prominently constructed and maintained across India, as well as in almost every nation where Sikhs reside. Gurdwaras are open to all, regardless of religion, background, caste, or race.
Worship in a gurdwara consists chiefly of singing of passages from the scripture. Sikhs will commonly enter the gurdwara, touch the ground before the holy scripture with their foreheads. The recitation of the eighteenth century ardās is also customary for attending Sikhs. The ardās recalls past sufferings and glories of the community, invoking divine grace for all humanity.
The Sikh faith also participates in the custom of "Langar" or the community meal. All gurdwaras are open to anyone of any faith for a free meal. People can enter and eat together and are served by faithful members of the community. This is the main cost associated with gurdwaras and where monetary donations are primarily spent.

Sikh festivals/events
Technically, there are no festivals in Sikhism. However, the events mostly centred around the lives of the Gurus and Sikh martyrs are commemorated. The SGPC, the Sikh organisation in charge of upkeep of the historical gurdwaras of Punjab, organises celebrations based on the new Nanakshahi calendar. This calendar is highly controversial among Sikhs and is not universally accepted. Sikh festivals include the following:

• Gurpurbs are celebrations or commemorations based on the lives of the Sikh gurus. They tend to be either birthdays or celebrations of Sikh martyrdom. All ten Gurus have Gurpurbs on the Nanakshahi calendar, but it is Guru Nanak Dev and Guru Gobind Singh who have a gurpurb that is widely celebrated in Gurdwaras and Sikh homes. The martyrdoms are also known as a shaheedi Gurpurbs, which mark the martyrdom anniversary of Guru Arjan Dev and Guru Tegh Bahadur. Since 2011 the Gurpurb of Guru Har Rai Sahib (March 14) has been celebrated as Sikh Vatavaran Diswas (Sikh Environment Day). Guru Har Rai was the seventh guru, known as a gentle guru man who cared for animals and the environment. The day is marked by worldwide events, including tree plantings, rubbish clearances and celebrations of the natural world.
• Nagar Kirtan involves the processional singing of holy hymns throughout a community. While practiced at any time, it is customary in the month of Visakhi (or Vaisakhi). Traditionally, the procession is led by the saffron-robed Panj Piare (the five beloved of the Guru), who are followed by the Guru Granth Sahib, the holy Sikh scripture, which is placed on a float.
• Visakhi which includes Parades and Nagar Kirtan occurs on 13 April. Sikhs celebrate it because on this day which fell on 30 March 1699, the tenth Guru, Gobind Singh, inaugurated the Khalsa, the 11th body of Guru Granth Sahib and leader of Sikhs till eternity.
• Bandi Chhor celebrates Guru Hargobind's release from the Gwalior Fort, with several innocent Hindu kings who were also imprisoned by Jahangir, on 26 October 1619. This day usually commemorated on the same day of Hindu festival of Diwali.
• Hola Mohalla occurs the day after Holi and is when the Khalsa gather at Anandpur and display their individual and team warrior skills, including fighting and riding.
   

Ceremonies and Customs
Guru Nanak taught that rituals, religious ceremonies, or idol worship are of little use and Sikhs are discouraged from fasting or going on pilgrimages. Sikhs do not believe in converting people but converts to Sikhism by choice are welcomed. The morning and evening prayers take around two hours a day, starting in the very early morning hours. The first morning prayer is Guru Nanak's Jap Ji. Jap, meaning "recitation", refers to the use of sound, as the best way of approaching the divine. Like combing hair, hearing and reciting the sacred word is used as a way to comb all negative thoughts out of the mind. The second morning prayer is Guru Gobind Singh's universal Jaap Sahib. The Guru addresses God as having no form, no country, and no religion but as the seed of seeds, sun of suns, and the song of songs. The Jaap Sahib asserts that God is the cause of conflict as well as peace, and of destruction as well as creation. Devotees learn that there is nothing outside of God's presence, nothing outside of God's control. Devout Sikhs are encouraged to begin the day with private meditations on the name of God.

Upon a child's birth, the Guru Granth Sahib is opened at a random point and the child is named using the first letter on the top left hand corner of the left page. All boys are given the last name Singh, and all girls are given the last name Kaur (this was once a title which was conferred on an individual upon joining the Khalsa). Sikhs are joined in wedlock through the anand kāraj ceremony. Sikhs are required to marry when they are of a sufficient age (child marriage is taboo), and without regard for the future spouse's caste or descent. The marriage ceremony is performed in the company of the Guru Granth Sahib; around which the couple circles four times. After the ceremony is complete, the husband and wife are considered "a single soul in two bodies."
According to Sikh religious rites, neither husband nor wife is permitted to divorce unless special circumstances arise. A Sikh couple that wishes to divorce may be able to do so in a civil court.
Upon death, the body of a Sikh is usually cremated. If this is not possible, any respectful means of disposing the body may be employed. The kīrtan sōhilā and ardās prayers are performed during the funeral ceremony (known as antim sanskār).

Baptism and the Khalsa
Khalsa (meaning "Sovereign") is the collective name given by Gobind Singh to all Sikhs, male or female, who have been baptised or initiated by taking ammrit in a ceremony called ammrit sañcār. The first time that this ceremony took place was on Vaisakhi, which fell on 30 March 1699 at Anandpur Sahib in Punjab. It was on that occasion that Gobind Singh baptised the Pañj Piārē—the five beloved ones, who in turn baptised Gobind Singh himself. The last name, Singh, meaning lion, is given to baptized Sikh males, and the last name Kaur, meaning princess/lioness, is given to baptized Sikh females. Baptised Sikhs are bound to wear the Five Ks (in Punjabi known as pañj kakkē or pañj kakār) at all times. The 5 items are: kēs (uncut hair), kaṅghā (small wooden comb), kaṛā (circular steel or iron bracelet), kirpān (sword/dagger), and kacchera (special undergarment). The Five Ks have both practical and symbolic purposes.

Information Source: https://en.wikipedia.org

 Online Resources to Know More About Sikhism: 

Sikhism - Wikipedia, the free encyclopedia: Sikhism (/ˈsɪkɨzəm/; Punjabi: ਸਿੱਖੀ, sikkhī, Punjabi pronunciation: [ˈsɪkːʰiː]) is a panentheistic religion founded during the 15th century in the Punjab region of the Indian subcontinent, by Guru Nanak and continued to progress through the ten successive Sikh gurus (the eleventh and last guru being the holy scripture ...

Sikhism Religion of the Sikh People: Sikhism preaches a message of Devotion and remembrance of God at all times, truthful living, equality of mankind and denounces superstitions and blind rituals. Sikhism is open to all through the teachings of its 10 Gurus enshrined in the Sikh Holy Book and Living Guru, Sri Guru Granth Sahib.
 

BBC - Religion: Sikhism: Guide to Sikhism, founded by Guru Nanak, including articles about Sikh customs, everyday life, rites and rituals and Sikh beliefs.

Sikhism - ReligionFacts: Sikhism emerged in 16th-century India in an environment heavily permeated with conflicts between the Hindu and Muslim religions. Its founding teacher, Guru ...

Introduction to Sikhism - The Sikh way of life: Sikhism, the youngest of the world religions, is barely five hundred years old. Its founder, Guru Nanak, was born in 1469. Guru Nanak spread a simple message ...

Gateway to Sikhism: A comprehensive web site on sikhism, sikh history and philosophy, customs and rituals,sikh way of life, social and religious movements, art and architecture, sikh ...