Yogamāyā

Yogamāyā · yoga-māyā, “the māyā of divine yoga”

Yogamāyā, also called Yoganidrā and Nidrādevī, is the supreme Śakti (divine power) of Bhagavān Vishṇu. She is a form of the Divine Mother and carries out the will of Bhagavān Vishṇu at the level of the whole creation.

She has a key part in the Kṛshṇa avatāra. She moved the child of Devakī that became Balarāma, she was born as the daughter of Yaśodā, and she was exchanged for the infant Kṛshṇa. When Kaṃsa seized her, she showed her divine form and declared that Kṛshṇa had already been born. Two Purāṇas tell her story in detail, the Bhāgavata Purāṇa and the Hari Vāṃśa Purāṇa. The Brahma Vaivarta Purāṇa also tells it. The Agni Purāṇa tells it briefly, and it gives the nine names with which Devendra praised her when she had slain Śumbha and the other rākshasas.

In the Bhāgavata Purāṇa, told by Śuka Maharshi to Parīkshit, Brahmā tells the devas on the shore of the Ocean of Milk that the māyā-śakti of Vishṇu, the Devī to be worshipped, by whom the whole world is deluded, will be born by an aṃśa (portion) at the command of Śrī Hari for the work of the avatāra. Śrī Hari calls her Devī and Kalyāṇī, the auspicious one, sends her to Gokula, and gives her fourteen names by which men will worship her and build holy shrines for her. She draws Śesha from Devakī’s womb into Rohiṇī’s, so that he is called Saṅkarshaṇa; she is born of Yaśodā, though she has no real birth; she puts the guards and the townspeople to sleep; and when Kaṃsa dashes her on a stone she rises into the sky as the eight-armed Devī, praised by the siddhas and gandharvas, and becomes renowned on earth in many places under many names. Through the rest of the Purāṇa the same Yogamāyā is the power of Śrī Hari by which he takes form, creates and withdraws the world, hides his glory, and plays his līlās: by her Śrī Kṛshṇa saves the gopa boys from the forest fire, stands beside every gopī in the rāsa, carries the people of Mathurā to Dvārakā and is present at once in every palace of his queens. Her workings are hidden even from Brahmā, the best of yogīs cannot cross her, and when Śrī Kṛshṇa returns to his own dhāma, Brahmā and Rudra praise her glory.

Source: Bhāgavata Purāṇa, Skandha 10, Chapters 1–4, 19, 33, 50, 69; Skandha 11, Chapter 31

Who she is

The Bhāgavata Purāṇa understands Yogamāyā as the yogaśakti (power of yoga) of Bhagavān Vishṇu, working in the world in a form with a person’s shape. Bhagavān Vishṇu speaks to her directly and gives her clear instructions. She is not a separate or independent power. She is an instrument of his will and acts fully in line with his purpose.

She is also called Ekāṃśā, the one who appears as a single aṃśa (portion) of the first Śakti. She is also counted as a form of Vishṇu-māyā.

Brahmā names her the māyā-śakti of Vishṇu, the Devī who is to be worshipped, by whom the world is deluded, and says that she, commanded by Śrī Hari, will be born by an aṃśa to accomplish the work of the devas. Śrī Hari addresses her as Devī and Kalyāṇī and calls her the supreme Īśvarī of all who have desires. When she rose from Kaṃsa‘s hands, the text says that the girl born after Śrī Hari, his younger sister, was the Devī herself, the Yogamāyā of Bhagavān Vishṇu.

Source: Bhāgavata Purāṇa, Skandha 10, Chapters 1–2, 4

Her fourteen names in the Bhāgavata

In the second chapter of the tenth Skandha, Bhagavān Vishṇu gives Yogamāyā her task. He also lists the names by which people on earth will worship her:

  • Durgā: she who helps one cross difficulties.
  • Bhadrakālī: she who brings good fortune.
  • Vijayā: she who gives victory.
  • Vaishṇavī: she who belongs to Vishṇu.
  • Kumudā: she who delights in the earth-world.
  • Caṇḍikā: she who is fierce toward the wicked.
  • Kṛshṇā: she who draws bhaktas (devotees) to her.
  • Mādhavī: she who came down in the Madhu-vaṃśa.
  • Kanyakā: she who gives ānanda (joy).
  • Māyā: she who makes the impossible possible.
  • Nārāyaṇī: she who lives as the life-breath in all living beings.
  • Īśānī: she who governs all.
  • Śāradā: she who destroys saṃsāra (the cycle of birth and death) and enemies.
  • Ambikā: she to whom the suffering turn for refuge.

People build sacred tīrtha places for her and offer her incense, flowers and food. The text says she gives every wish as a vara (a boon).

Śrī Hari gives the names in this order, each with its meaning. Kumudā is she who makes the earth (ku) glad. Śāradā is also she who is worshipped in the Śarat season, the autumn. He tells her: “You are the supreme Īśvarī of all who have desires. Men will worship you with dhūpa (incense), pushpa (flowers), naivedya (food offerings) and the rest, for you grant all desires as varas. On earth men will call you by these names and build puṇya-kshetras (holy shrines) for you.”

Source: Bhāgavata Purāṇa, Skandha 10, Chapter 2

Her task in the birth of Kṛshṇa (Bhāgavata)

Bhagavān Vishṇu gave Yogamāyā three instructions before he came down to earth.

  1. Go to Gokula. She was to go to Nanda‘s settlement, where Vasudeva‘s wife Rohiṇī was living in safety.
  2. Move Balarāma. She was to draw the child of Śesha out of Devakī‘s womb and place it in Rohiṇī’s womb, so that the divine child would be born safely in Gokula as Balarāma.
  3. Be born as Yaśodā’s daughter. Bhagavān Vishṇu said: “I shall be born as Devakī’s son. You shall be born as Yaśodā’s daughter. On the night I am born, Vasudeva will carry me to Gokula. You will be carried back to Mathurā. When Kaṃsa seizes you, you will show your divine form and announce my birth.”

Yogamāyā accepted all this and walked around Bhagavān Vishṇu in respect. Then she carried out the instructions. She moved the child to Rohiṇī, and to everyone it looked like a miscarriage. She was then born as Yaśodā’s daughter on the very night that Kṛshṇa was born in Mathurā.

Śuka gives the whole commission. Kaṃsa, son of Ugrasena, supported by Jarāsandha and his followers, had driven the Yādavas from their land and killed six sons of Devakī. Devakī conceived for the seventh time, and in that womb was Śesha, the kalā (portion) of Vishṇu, whom the mahātmās call Ananta. Śrī Hari, the ātmā of all and himself the protector of the Yādavas, saw their fear of Kaṃsa and commanded Yogamāyā: “O Devī! O Kalyāṇī! Go to Gokula, beautiful with gopālakas and cows. In Nanda‘s Gokula lives Rohiṇī, wife of Vasudeva; his other wives, afraid of Kaṃsa, are living in hidden places. The embryo in Devakī’s womb is my aṃśa named Śesha. Draw out that embryo and place it well in the womb of Rohiṇī. After that I will be born as Devakī’s son, with jñāna, bala and the rest, and you will be born as the daughter of Yaśodā, wife of Nanda.”

Śrī Hari also said that because Yogamāyā draws (saṅkarshaṇa) the embryo from Devakī into Rohiṇī, people will call the boy Saṅkarshaṇa; because he delights people, Rāma; and because he is the best of the strong, Bala. Yogamāyā said “So be it”, made pradakshiṇa (circled him with reverence), went to earth and did exactly as he had said. When she drew out Devakī’s embryo and placed it in Rohiṇī, the people of the city cried out, “Alas! Devakī’s embryo is lost.”

Source: Bhāgavata Purāṇa, Skandha 10, Chapter 2

The exchange and Kaṃsa’s failure (Bhāgavata)

On the night of Kṛshṇa‘s birth, Yogamāyā put all the prison guards and all the people of Gokula into deep sleep. Through her power they lost all awareness of their senses. This let Vasudeva carry the infant Kṛshṇa out of the prison and across the Yamunā to Gokula without being seen. She also made sure that Yaśodā, after her own delivery, fell into deep sleep and did not even know whether she had borne a boy or a girl.

Vasudeva laid Kṛshṇa beside the sleeping Yaśodā and took Yogamāyā, in the form of the baby girl, back to Mathurā. In the prison Kaṃsa seized the baby girl and dashed her against a stone. She rose into the air in her eight-armed divine form and said: “O fool! What use is throwing me? The one who will destroy you has already been born. He has already arrived elsewhere.” Then she disappeared.

Śuka tells the night in full. At the very time that Vasudeva took up his son, Yogamāyā, who has no real birth, was born of Yaśodā, wife of Nanda. She took from the gate-keepers and the townspeople every working of the senses and made them sleep; the great doors of the prison, shut with iron bolts and chains, opened by themselves before Vasudeva, and in Nanda’s settlement he found the gopālakas sleeping, unaware of their bodies, by the power of Yogamāyā. He laid his son beside Yaśodā, took her daughter, laid the girl beside Devakī and put the fetters back on his own feet. Yaśodā knew only that she had given birth, not whether the child was a boy or a girl.

When the guards heard the infant’s cry, they ran to Kaṃsa. Devakī held the girl close, hidden in the end of her sārī, and begged him: “This girl is your niece. It is not fit for you to kill a girl-child. My sons have been killed; spare this last child of mine.” Kaṃsa pushed her away, dragged the infant from her hand, seized her by both feet and struck her down upon the top of a stone.

That girl, born after Śrī Hari, was the Devī herself. She flew up from his hand into the sky and was seen with eight great arms. She wore divine garments, garlands and ornaments set with gems, and was anointed with sandal and other unguents. In her eight hands she held the divine bow, the arrows, the śūla (trident), the kavaca (armour), the sword, the śaṅkha, the cakra and the gadā. Siddhas, Cāraṇas, gandharvas, apsarases, kinnaras and nāgas brought great offerings and praised her. In a deep voice she said to Kaṃsa: “O fool! What is the use of killing me? Your former enemy, who will put an end to you, has already been born somewhere. Do not torment the helpless in vain.” Then that Devī, the Yogamāyā of Bhagavān Vishṇu, became renowned on earth in different places under different names.

Source: Bhāgavata Purāṇa, Skandha 10, Chapters 3–4

The six sons of Devakī (Bhāgavata)

Long after, in Sutala, Śrī Kṛshṇa told Bali the history of Devakī‘s six sons whom Kaṃsa had killed. In the Svāyambhuva manvantara they were the six sons of Marīci Prajāpati by Ūrṇā, and they were devatās. Seeing Brahmā turn towards his own daughter, they laughed, and for that wrong act they took birth as rākshasas, the sons of Hiraṇyakaśipu. Yogamāyā carried them off and placed them in the womb of Devakī; they were born as her sons and were killed by Kaṃsa. To take them back to their mother, Balarāma and Śrī Kṛshṇa, urged by Devakī, took the support of Yogamāyā and entered Sutala-loka. There Bali said to Śrī Kṛshṇa that even the lords of yoga, Nārada and the others, do not know his Yogamāyā exactly as it is.

Source: Bhāgavata Purāṇa, Skandha 10, Chapter 85

Yogamāyā, the power of Śrī Hari (Bhāgavata)

Through the whole Bhāgavata, Yogamāyā is the power of Śrī Hari by which he creates, sustains and withdraws the world and by which he moves among beings in his avatāras. The text speaks of her in these places, in its own order:

  • The form for human līlā. Uddhava tells Vidura that, wishing to show the world the power of his Yogamāyā, Bhagavān Kṛshṇa took a form fitting for human līlās, the summit of auspiciousness, which adorned the very ornaments it wore (Skandha 3, Chapter 2).
  • Sleep and the līlās. Vidura asks Maitreya how Parameśvara withdraws the world into the space of his consciousness and sleeps in Yogamāyā; Maitreya undertakes to tell in order the līlās Bhagavān Vishṇu reveals through Yogamāyā for creation, maintenance and dissolution (Skandha 3, Chapter 5).
  • The Virāṭ form. With Kāla, the karma of the jīvas and his own power, Bhagavān Vishṇu appeared as the Virāṭ form by his Yogamāyā, and no one can describe it fully (Skandha 3, Chapter 6).
  • Varāha. The ṛshis of Janaloka, Tapoloka and Satyaloka, praising Bhagavān Varāha, say the whole jagat is bewildered by its link with the guṇas of his Yogamāyā (Skandha 3, Chapter 13). Hiraṇyāksha taunted him that Yogamāyā was his only strength (Skandha 3, Chapter 18).
  • Before the Kumāras. Śrī Hari says his Yogamāyā is unbroken and of unfailing glory. By Yogamāyā he showed the Kumāras the height of his supreme aiśvarya, and they thrilled and spoke with joined hands. Brahmā tells the devas that even the best of yogīs cannot cross his Yogamāyā (Skandha 3, Chapter 16).
  • The spider and its web. Kardama Prajāpati says that before creation Śrī Hari alone was; the Yogamāyā whose ground is Śrī Hari himself is not separate from him, holds the śaktis of sattva, rajas and tamas, and through her he brings forth the world from himself, as the spider brings forth its web, sustains it, and in pralaya (dissolution) withdraws it (Skandha 3, Chapter 21).
  • Brahmā’s stuti. Brahmā says to Śrī Kṛshṇa that Yogamāyā is under his control and that he plays by spreading her out, so that no one can know where, how or how many his līlās are (Skandha 10, Chapter 14).
  • The forest fire. Śrī Kṛshṇa saved the gopa boys and the cows from the forest fire by his Yogamāyā, and seeing his power they thought he was a deva (Skandha 10, Chapter 19).
  • Govardhana. When Śrī Kṛshṇa held up the mountain for seven days, Indra, seeing the greatness of his Yogamāyā, was astonished; his pride left him and he turned his clouds back (Skandha 10, Chapter 25).
  • The rāsa. In Śarat, when the jasmines bloomed in the nights, Śrī Kṛshṇa took refuge in his Yogamāyā and resolved to sport (Skandha 10, Chapter 29). Śrī Kṛshṇa, master of Yogamāyā, entered between each two gopīs, so that each saw him at her own side; though he delights in himself alone and is complete, by Yogamāyā he became as many as there were gopīs. The people of Gokula saw no fault in him, for, enchanted by his Yogamāyā, each saw his own wife beside him (Skandha 10, Chapter 33).
  • Before Devakī and Vasudeva. When Śrī Kṛshṇa saw that his parents had come to know his true nature, he spread out his Yogamāyā, which bewilders people, and came to them as their son. Śuka says that Śrī Kṛshṇa, the ātmā of the world, had become human by Yogamāyā (Skandha 10, Chapter 45).
  • Dvārakā. By the power of Yogamāyā, Śrī Kṛshṇa carried all the people of Mathurā to Dvārakā (Skandha 10, Chapter 50).
  • Nārada in Dvārakā. Wishing to know the Yogamāyā of Śrī Kṛshṇa, Nārada went from palace to palace and found him in each, doing the acts of a gṛhastha, and in one place moving with his true form hidden among the ministers and the antaḥpura. Nārada said: “Your yogamāyās cannot be seen even by Brahmā and the others; but by serving your feet they have shone in my heart.” Śuka closes: Nārāyaṇa took on Yogamāyā for the welfare of all beings, followed the ways of men, and was served by the sixteen thousand with loving glances (Skandha 10, Chapter 69).
  • Balarāma and Romaharshaṇa. Balarāma offered the maharshis to give Romaharshaṇa long life, strength and keen senses by Yogamāyā (Skandha 10, Chapter 78).
  • The stuti at Kurukshetra. Dharmarāja and Śrī Kṛshṇa’s friends say he has taken form by Yogamāyā and descended to protect the Vedas lost through time (Skandha 10, Chapter 83). The maharshis bow to Śrī Kṛshṇa, whose glory is covered by his Yogamāyā, the innermost consciousness of every person (Skandha 10, Chapter 84).
  • Vasudeva’s stuti. Vasudeva says to his two sons that the guṇas, and pleasure, pain and delusion, are imagined by Yogamāyā in Parabrahma (Skandha 10, Chapter 85).
  • Vṛka. When the rākshasa Vṛka pursued Bhagavān Śiva to test his vara, Nārāyaṇa, remover of fears, became a brahmacārī by Yogamāyā and went out to meet the rākshasa (Skandha 10, Chapter 88).
  • The return to the dhāma. When Śrī Kṛshṇa reached his own dhāma by yoga, Brahmā, Rudra and the others, amazed, praised the glory of his Yogamāyā and went each to his own loka (Skandha 11, Chapter 31).

Source: Bhāgavata Purāṇa, Skandha 3, Chapters 2, 5–6, 13, 16, 18, 21; Skandha 10, Chapters 14, 19, 25, 29, 33, 45, 50, 69, 78, 83–85, 88; Skandha 11, Chapter 31

Yogamāyā and the Kātyāyanī Vrata

Later in the tenth Skandha, the gopikās (cowherd women) of Vṛndāvana keep the Kātyāyanī vrata (vow) in the month of Mārgaśīrsha. They pray that Kṛshṇa become their husband. The Bhāgavata says plainly that the Devī they worship in this vrata is Kātyāyanī, another form of Yogamāyā. So Yogamāyā arranges Kṛshṇa’s birth, and she also receives the prayers of the gopikās and turns their bhakti (devotion) toward Kṛshṇa.

In the Brahma Vaivarta Purāṇa

The Brahma Vaivarta Purāṇa tells the same events in the Śrī Kṛshṇa Janana Khaṇḍa. There she is named more directly as Ekāṃśā, the one who appears as Yaśodā’s daughter. Her eight-armed words to Kaṃsa are described in a similar way. This Purāṇa speaks of her as the personal divine power (nija śakti) of Bhagavān Vishṇu. It does not give the fourteen names that the Bhāgavata gives.

In the Hari Vāṃśa Purāṇa

Her task

Bhagavān Vishṇu decided to be born as the eighth child of Devakī. He went down to Pātāla and brought back the life-forces of the six Shaḍgarbhas who lay sleeping there. These six were sons of Kālanemi. Hiraṇyakaśipu had laid a śāpa (curse) on them that they would be killed by their own father.

Bhagavān Vishṇu gave these six life-forces to Nidrādevī (Yoganidrā) with this task: “Go to Devakī’s house. Place these lives in her womb one by one. Kaṃsa will kill them, and his effort will come to nothing. Then move Devakī’s seventh pregnancy, the child of the Moon’s aṃśa, into Rohiṇī’s womb. He will be called Saṃkarshaṇa. Finally, you yourself will be born as the ninth child to Yaśodā, wife of Nandagopa, at the same midnight hour in which I am born to Devakī. After that we shall be exchanged. I shall go to Yaśodā and you to Devakī.”

Bhagavān Vishṇu also told her what would follow. Kaṃsa would seize her and hurl her against a stone. At that moment she was to leave the infant body, show her true divine form, and go up to her appointed place.

The two births

Bhagavān Vishṇu and Yogamāyā entered the wombs of Devakī and Yaśodā at the same moment. When the months were complete, Devakī gave birth to Kṛshṇa and Yaśodā gave birth to a daughter. Both births took place on the same night, under the Abhijit nakshatra (lunar star) at the auspicious Vijaya muhūrta (hour). Vasudeva took the newborn Kṛshṇa to Yaśodā’s house in secret and placed him with her. He brought Yaśodā’s daughter back and laid her beside Devakī.

The exchange and Kaṃsa’s attack

Vasudeva told Kaṃsa that a girl had been born. Kaṃsa believed that the prophecy spoke only of an eighth child who would be a boy. He came to the prison with guards and demanded the infant. Devakī protested that this was a girl, and seven sons had already been killed. Kaṃsa seized the baby anyway and dashed her against a stone.

Her true form

Struck against the stone, Yogamāyā flew into the sky. At once she left the infant body and appeared in her true form. She was beautiful and four-armed, with a face like the moon and loose hair. Her body was sweet with divine perfumes and she wore garlands. The hosts of devas praised her. She let out a great peal of laughter and fixed her fierce gaze on Kaṃsa, and she said:

“O Kaṃsa! You struck me against the stone only to bring about your own ruin. When your enemy drags you to your death, I shall tear open your chest and drink your warm blood.”

Then she left through the sky with her attendants.

Her nature as the Śakti of Bhagavān Vishṇu

Before she took up this task, Bhagavān Vishṇu taught Yoganidrā the Āryā Stotra (a stotra is a hymn of praise). It describes her many forms. She is Nārāyaṇī, never apart from Bhagavān Vishṇu. The stotra addresses her as:

  • Siddhi, Kīrti, Śrī, Vidyā, Mati and Dhṛti, the powers and perfections of all beings.
  • Saṃdhyā, Rātri, Prabhā, Nidrā and Kālarātri, the divisions of time.
  • Āryā, Kātyāyanī, Kauśikī and Brahmacāriṇī, by her sacred names.
  • Nandagopa-sutā, the daughter of Nandagopa, which names her birth in Gokula.
  • Vindhyavāsinī, she who lives on the Vindhyaparvata, her home after the avatāra.
  • The Antarvedī of the yajñas (fire rituals), the Dakshiṇā of the ṛtvijas (priests), the Sītā of farmers, and the Dharaṇī of all beings.
  • Pārvatī among women, Sarasvatī in the work of Vālmīki, Smṛti in the work of Dvaipāyana, Arundhatī among virtuous women, and the famous Indrāṇī.

She fills the whole universe, moving and unmoving. She protects her devotees in battles, fires, dangers in the forest, captivity, exile and every time of crisis.

Her names and pūjā

Bhagavān Vishṇu told her she would be known as Kauśikī, because of her link with the Kuśika gotra (family line). Indra would consecrate her and take her as his sister. The Vindhyaparvata would be her eternal home. There she would roam with bhūtas, pretas and piśācas (spirits) and accept offerings of meat. People would give her pūjā on the Navamī of the dark fortnight (Kṛshṇa Navamī) and the Ekādaśī of the bright fortnight. Those who give her pūjā are freed from all difficulties, sickness, imprisonment, loss of children and the fear of death.

The Āryā Stotra, the hymn Bhagavān Vishṇu himself taught her, is the way her grace reaches people. A person who recites it in purity at dawn gets the wished-for fruits within three months. A supreme vara (boon) comes within six months. Divine sight comes after three months of pūjā, and full siddhi (spiritual power) comes within a year.

After she showed herself to Kaṃsa, the Hari Vāṃśa says the Yādavas honoured her. She became respected as if she were Vasudeva‘s own daughter, born from the aṃśa of Prajāpati. She is honoured as the guardian devī of Kṛshṇa.

In the Agni Purāṇa

Agni Deva tells the account briefly in the Agni Purāṇa, in his description of the Harivaṃśa. To remove the burden of the earth, Bhagavān Vishṇu sent Yogamāyā, and through her power the six sons of Hiraṇyakaśipu in their former birth were born to Devakī by Vasudeva. Balarāma became Devakī’s seventh garbha (child in the womb). He was moved into Rohiṇī and was called Rauhiṇeya. Then Hari was born, four-armed, at midnight on the ashṭamī of the dark fortnight of Śrāvaṇa, and became a two-armed child. Vasudeva, afraid of Kaṃsa, took the child and laid him beside Yaśodā. He took Yaśodā’s daughter and laid her beside Devakī.

Kaṃsa heard the infant’s cry. Devakī tried to stop him, but he dashed the infant on a stone, saying, “Your eighth garbha is the cause of my death.” The girl, thrown down, flew up into the sky and said to Kaṃsa: “Kaṃsa, what use is throwing me down? One who is everything to the devas has been born to remove the burden of the earth. He will kill you.” Saying this, she vanished.

Devendra’s nine names

The Agni Purāṇa says that she is the Devī who long ago slew Śumbha and the other rākshasas, and that Devendra then praised her: “Āryā! Durgā, Vedagarbhā, Ambikā, Bhadrakālī, Bhadrā, Kshemyā, Kshemakarī, Naikabāhu: I bow to you who bear these names.”

  • Āryā: the noble one.
  • Durgā.
  • Vedagarbhā: she who holds the Vedas within.
  • Ambikā: the Mother.
  • Bhadrakālī.
  • Bhadrā: the auspicious one.
  • Kshemyā: the giver of welfare.
  • Kshemakarī: she who brings well-being.
  • Naikabāhu: the many-armed.

Phalaśruti: one who recites these names at the three sandhyās (the junctions of the day) obtains all desires.

Source: Agni Purāṇa, Chapter 12

Sources

  • Bhāgavata Purāṇa, Skandha 3, Chapters 2, 5–6, 13, 16, 18, 21; Skandha 10, Chapters 1–4, 14, 19, 22, 25, 29, 33, 45, 50, 69, 78, 83–85, 88; Skandha 11, Chapter 31
  • Brahma Vaivarta Purāṇa, Śrī Kṛshṇa Janana Khaṇḍa, Chapter 7
  • Hari Vāṃśa Purāṇa, Vishṇu Parva, Chapters 2–4
  • Agni Purāṇa, Chapter 12