Amitabha is the principal Buddha in Pure Land Buddhism. "Amitabha" is translatable as "Infinite Light," hence Amitabha is also called "The Buddha of Immeasurable Life and Light".
According to the "Larger Sutra of Immeasurable Life", Amitabha was, in very ancient times and possibly in another system of worlds, a monk named Dharmakara. He then resolved to become a Buddha. Dharmakara's eighteenth vow was that any being in any universe desiring to be born into Amitabha's Pure Land and calling upon his name even as few as ten times will be guaranteed rebirth there.
The sutra goes on to explain that Amitabha, after accumulating great merit over countless lives, finally achieved Buddhahood and is residing in his Pure land, Sukhavati. It is situated in the uttermost west, beyond the bounds of our own world.
Amitabha is the center of a number of mantras in Buddhist Vajrayana practices. In Tibetan version, it is "Om ami dewa hri". The Japanese version is "On amirita teizei kara un".
In addition to using the mantras listed above, many Buddhism schools invoke Amitabha's name in a practice known as chanting Buddha's Name.
Amitabha's name is a compound of the Sanskrit words amita ("without bound, infinite") and abha ("light, splendor"). Consequently, the name is to be interpreted as "he who possesses light without bound, he whose splendor is infinite".
Repeating on chanting Amitabha can make the practitioner bring all his or her attention upon that Buddha. This may be done vocally or mentally, and with or without the use of Buddhist prayer beads. Those who practice this method often commit to a fixed set of repetitions per day. According to tradition, the second patriarch of the Pure Land school, Shandao, is said to have practiced this day and night without interruption, each time emitting light from his mouth. Therefore he was bestowed with the title "Great Master of Light" (光明大師).
Chanting Amitabha's Name is to be chanted slowly and the mind emptied out after each repetition. When idle thoughts arise, the chanting is repeated again to clear them. With constant practice, the mind progressively empties and the meditator attains samadhi.
In most Pure Land traditions, mindfully chanting of the name of Amitabha is viewed as allowing one to obtain birth in Amitabha's pure land, Sukhavati. It is felt that this act would help to negate vast stores of negative karma that might hinder one's pursuit of Buddhahood. Sukhavati is a place of refuge where one can become enlightened without being distracted by the sufferings of our existence.
Practitioners claim there is evidence of dying people going to the pure land, such as:
Knowing the time of death: some prepare by bathing and reciting the name of the Buddha Amitabha.
The "Three Saints of the West": Amitabha Buddha, Avalokiteśvara and Mahasthamaprapta appear and welcome the dying person. Visions of other Buddhas or Bodhisattvas are disregarded as they may be bad spirits disguising themselves, attempting to stop the person from entering the Pure Land.
Records of practicing Pure Land Buddhists who have died have been known to leave sarira, or relics, after cremation.
In Buddhist teaching, souls who enter the Pure Land leave the body through the posterior fontanelle at the top of the skull. Hence, this part of the body stays warmer longer than the rest of the body. The Verses on the Structure of the Eight Consciousnesses reads: "to birth in saints the last body temperature in top of head, to deva in eyes, to human in heart, to hungry ghosts in belly, to animals in knee cap, to the hells-realm in sole of feet."