Khema "senility" (ch: chènmó 讖摩 or kǎimǎ 凱瑪) is a disciple of the Buddha, proclaimed by him to be the first of the nuns in rank (except for the deans Mahaprajapati Gautami and Kisa Gautami) and in wisdom. Poems of the Therigatha are attributed to her.
Originally from Sagala in the kingdom of Magadha, she was of royal blood and of great beauty, with golden skin. She became the first lady of the gynaeceum of king Bimbisâra, patron saint of Buddhism.
In love with beauty, she always refused the king's invitations to attend the Buddha's sermons, although she was tempted, for fear of being criticized by the sage of the Shakyas, who was said to hold physical perfection in low esteem. To persuade her, Bimbisâra had recourse to a ruse: he had his musicians sing the charms of the wood where the Buddha's monastery was located.
Intrigued, Khema finally went there. Seeing her approaching from afar, Gautama made appear at her side the form of a young girl whose beauty surpassed even his own. Fascinated, she contemplated the girl, secretly comparing herself to her.
The Buddha then gradually aged the form in front of her; it became a stunted old woman, then a corpse, and finally a pile of bones. Khema, who had acquired many merits in her previous lives and vowed to become the first nun before Padumuttara Buddha, having at that time sold her hair as an offering to him, was able to realize immediately the impermanence of conditioned phenomena.
Fifteen days later, she became an arhat, and then asked her husband for permission to become a nun, which he gladly granted.
Gautama proclaimed her to be the first for wisdom. She was in charge of the training of the nuns and often preached to the laity. People came to her for explanations of doctrine.
One day, the king Pasenadi of Kosala came to ask her why the Buddha had refused to take a stand for any of the following four affirmations: an awakened being continues to exist after death; he ceases to exist at his death; he exists and does not exist at the same time; he no longer exists, but at the same time he does not cease to exist.
Khema explained to him in a convincing way how none of these propositions could apply to a being who had totally escaped from conditioned materiality. Later, when Pasedani had the opportunity to question the Buddha in person, he was amazed to hear him express himself in the same terms as Khema, word for word.
Khema often appears in the Jatakas under different forms. She is once the wife of Gautama and once his daughter-in-law, and once the wife of Sariputta.
In Sri Lankan legends, she is the one who collects the relic of Buddha's tooth from the ashes of his funeral pyre, a relic that is now kept in the Temple of the Tooth in Kandy.