Musical Dimension
Rag Ramkali
Out of the thirty-one principal rags in the Guru Granth Sahib, Rag Ramkali (a musical mode) has been designated eighteenth place in the sequence. Under this rag, the Bani of six Gurus, four Bhagats, and three Gursikhs (a Sikh who follows the Guru’s way) is recorded from page 876 to 974 of the Guru Granth Sahib. It includes one hundred sixty-six Sabads by Guru Nanak Sahib, seven by Guru Angad Sahib, ninety-one by Guru Amardas Sahib, six by Guru Ramdas Sahib, one hundred sixty-eight by Guru Arjan Sahib, three by Guru Teghbahadar Sahib, twelve by Bhagat Kabir, four by Bhagat Namdev, and one each by Bhagat Ravidas, and Bhagat Beni.
Bhai Joginder Singh Talwara, Bani Biura, part 1, page 103-110.
Bani ‘Sadu’ revealed by Baba Sunder and ‘Ramkali Ki Var’ by Bhai Balvand and Bhai Satta are also recorded under this rag. Compositions of ‘Sidh Gosti’ and ‘Oankar’ by Guru Nanak Sahib, and ‘Anand’ by Guru Amardas Sahib are also revealed in this rag.

Ramkali is an old and famous rag. The names Ramkriti, Ramkriya, Ramgiri, Ramkari, and Ramkeli are also found to be used for this rag.
Prof. Kartar Singh, Gurmat Sangit Darpan, part two, page 55-56.
It has an important place in the rags sung in the morning. This is a rag of compassion. This rag has been specially adopted by the Nath-Yogis.
Nath panth or sampradaya originated from the Shaiva tradition in Hinduism. It is one of the most prominent sects in the Yog tradition. The term ‘nath’ (literally, a master) is also used for the chief mahant of yogis, to whom all the yogis bow their heads. They consider Shiva (one of the three major gods/deities in Hinduism) as their first Lord or Master (Adi Nath). Its founder was Matsyendranath or Machhindranath from the early tenth century, which was further developed by one of his disciples Gorakhnath in the early eleventh century. Nath tradition primarily combined elements of Shaivism, Buddhism as well as hath and tantric yog. There are nine main Yogis in the Nath tradition. They are also mentioned in the Guru Granth Sahib, for instance: guṇ gāvahi nav nāth dhanni guru sāci samāio. -Guru Granth Sahib 1390.
The contributors to the Guru Granth Sahib, while having a dialogue with Nath-Yogis or Sidhs,
The term Siddha, widely used in Indic religious traditions, literally means a wise or accomplished yogi. It also refers to one of the eighty-four accomplished yogis who were believed to have possessed the eight siddhis (extraordinary physical and spiritual capabilities). 
have also revealed most of their compositions in this rag. ‘Sidh Gosti’ revealed by Guru Nanak Sahib under this rag, is an example of that.

In the Guru Granth Sahib, Sabad is considered to be more important than rag. Rag is the means through which all-pervasive IkOankar is to be enshrined in the heart. Referring to Rag Ramkali in the Guru Granth Sahib, Guru Amardas Sahib states that if by singing this rag, the all-pervading IkOankar dwells within, only then should one be considered to be adorned: rāmkalī rāmu mani vasiā tā baniā sīgāru. -Guru Granth Sahib 950.

In the Guru Granth Sahib, another rag named Rag Ramkali Dakhni is also recorded under Rag Ramkali. This rag is available only in Gurmat Sangit (Sikh Devotional Music); it is not found in Hindustani or Carnatic music.

Scholars have differing opinions about Rag Ramkali. In the Bharat school of thought of Hindustani Music, it is considered to be a ragini of Rag Hindol, and in the Hanuman school of thought, it has been considered to be a ragini of Srirag.
Prof. Kartar Singh, Gurmat Sangit Darpan, part two, page 57.
Bhai Kahn Singh Nabha has considered it to be an aurav-sampuran ragini of Bhairav that.
Bhai Kahn Singh Nabha, Mahan Kosh, page 1034.

Bhai Avtar Singh Bhai Gurcharn Singh have mentioned three different forms of Rag Ramkali. First is aurav-sampuran, in which Ni komal (flat) and Ma shudh (natural) are used. In the second one, both Ni are used. In the third one, both Ma, and both Ni are used. Pa is vadi (prominent note) and Sa is samvadi (sub-prominent note).
Bhai Avtar Singh Bhai Gurcharn Singh, Gurbani Sangit Prachin Rit Ratnavali, part two, page 525.
The third form is more prevalent. S. Gian Singh Abbottabad, Dr. Gurnam Singh, and Rag Nirnayak Committee
Principal Sukhwant Singh (editor), Guru Nanak Sangit Padhati Granth, part-1, page 55.
have described this rag as follows:

Description of Rag Ramkali
That: Bhairav.
Svar (notes): Re and Dha komal (flat), both Ma, both Ni, rest all shudh (natural).
Varjit Svar (forbidden notes): Re (in aroh - ascending scale).
Jati (class): sharav-sampuran (some scholars believe it to be sampuran-sampuran).
Vadi (prominent note): Pa.
Samvadi (sub-prominent note): Re.
Aroh (ascending scale): Sa, Ga Ma Pa, Dha (komal - flat) Ni Sa (tar saptak - upper octave).
Avroh (descending scale): Sa (tar saptak - upper octave) Ni Dha (komal - flat), Pa, Ma (tivar - sharp) Pa Dha (komal - flat) Ni (komal - flat) Dha (komal - flat) Pa, Ga Ma Re (komal - flat), Sa.
Mukh Ang/Pakar (Main Part): Dha (komal - flat) Pa, Ma (tivar - sharp) Pa Dha (komal - flat) Ni (komal - flat) Dha (komal - flat) Pa, Ga Ma Re (komal - flat) Sa.

Singing Time
The first quarter of the day.