Kātyāyana or Mahākātyāyana (Sanskrit and Pali: Kaccāna, Mahākaccāna or Mahākaccāyana) was a disciple of Gautama Buddha.
He is listed among his top ten disciples and was known for his exposition of the Dharma.
In Thai Buddhism, he is also known as Phra Sangkajai and often portrayed as extremely corpulent.
Kātyāyana was born into a Brahmin family in the city of Ujjayini (Ujjain) and received a classical Brahminical education, which included the study of the Vedas.
He studied assiduously under Asita, who predicted that Prince Siddhartha would become a cakravartin, a great worldly ruler or Buddha. Kātyāyana was a religious adviser to King Candappajjota, ruler of the state of Avanti.
At the king's request, Kātyāyana set out with a group of seven friends to visit the Buddha in Sravasti, and attained enlightenment by listening to him preach. He was ordained and made numerous conversions in Avanti.
In the Madhura Sutta, King Avantiputta of Madhurā approached Kātyāyana some time after the Buddha's Parinirvāṇa with a question regarding the Brahmin's claims of superiority because of their caste. Kātyāyana points out that wealth empowers people regardless of caste and that Brahmins experience the same results of good or bad conduct in the same way as those of other castes.
In the time of the Buddha Padmottara, Kātyāyana made the decision to achieve greatness after hearing the praise of another monk who shared his name. In this lifetime, he was a vidyādhara and offered the Buddha three kanikāra flowers. After building a hut in the shape of a lotus and naming it Paduma (in pali lit. "lotus"), he became a king named Pabhassara after thirty kalpas.
He is also said to have been a vidyādhara at the time of Sumedha Buddha .
At the time of the Buddha Kāsyapa was a householder in Benares. He offered a golden brick to a caitiya that housed the Buddha's remains and made a vow that in the future his body would have a golden complexion.
There is a famous "incident" reported in verse 43 of the Dhammapada commentary in which a man named Soreyya was traveling with a friend and noticed that Kātyāyana was adjusting his robes.
Seeing her golden complexion, Soreyya began to fantasize that Kātyāyana should become his wife or that his wife's complexion should be like Kātyāyana's. Because of the nature of this thought, she became a woman. She married a wealthy man from Taxila and bore him two sons.
Soreyya later approached Kātyāyana and explained the situation, apologizing for her misconduct in thought. Kātyāyana accepted his apology, thanks to which Soreyya regained his male form.
Another story recounts the incident of a man named Vassakāra, a minister of King Ajātaśatru. After seeing Kātyāyana descending from Mount Gridhrakūta, Vassakāra claimed that he looked like a monkey.
The Buddha warned him that, because of his claim, he would be reborn as a monkey in Veṇuvana As a precaution, Vassakāra stocked that area with fruit trees and after death was reborn as the Buddha had predicted.
Tradition attributes to Katyāyana the authorship of two late Pāli canonical texts:
The Nettipakarana, a commentary on Buddhist doctrine. The Peṭakopadesa, a treatise on exegetical methodology. However, it is possible that these texts were composed by a school descended from him. Tradition associates his name with a Buddhist community in Avanti, the region believed to have been the origin of the Pāli Canon.
Tradition also holds that Mahākātyāyana was the author of verses 494-501 of Theragāthā, where he gives advice to meditators.
In the Lotus Sutra
Chapter 3 of the Lotus Sutra entitled "Simile and Parable," Mahākātyāyana is one of four disciples to understand the Buddha's intention in his sermon.
In Chapter 6 titled "Conferring Prophecy," the Buddha confers prophecies of enlightenment on disciples Mahākāśyapa, Subhūti, Mahākātyāyana and Maudgalyāyana. It is predicted that Mahākātyāyana will become a Buddha named Jāmbūnadābhāsa.
Nāgārjuna cites a text he calls Kātyāyanavavāda ("Advice to Kātyāyana") in his Mūlamadhyamakakārikā (15.7). This text appears to have been a Sanskrit parallel to the Pāli Kaccānagotta Sutta .