Mahāsthāmaprāpta (Ch 大勢至 Da Shì Zhì, Jp. 勢至 Seishi Vi Đại Thế Chí Bồ tát) is a bodhisattva that represents the power of wisdom and is often depicted in a trinity with Amitabha and Avalokitesvara, especially in Pure Land Buddhism. In Chinese Buddhism, he is usually portrayed as a woman, with a likeness similar to Guan Yin. He is also one of the Japanese Thirteen Buddhas.
Unlike most bodhisattvas, Mahasthamaprapta is one of the lesser known bodhisattvas, but is still regarded as a powerful bodhisattva nonetheless. In the Shurangama Sutra, Mahasthamaprapta tells of how he gained enlightenment through the practice of Buddha recitation, or continuous pure mindfulness of the Buddha, to obtain samadhi. In the Contemplation Sutra, Mahasthamaprapta is symbolized by the moon (wisdom) while Avalokitesvara is symbolized by the sun.
In Shingon Buddhism, the mantra used for Seishi in Japanese is:
On san zan zan saku sowaka
From the Sanskrit mantra:
The translation of this mantra is generally Om, may defilements be removed, hail.