Anussati

 Anussati (Pāli; Sanskrit: Anusmriti) means "recollection," "contemplation," "remembrance," "Meditation" and "Mindfulness." In Buddhism, anussati refers to either:

    specific meditative or devotional practices, such as recollecting the sublime qualities of The Buddha, which lead to mental tranquillity and abiding Joy; or,
    meditative attainment, such as the ability to recollect past lives.

Sets of recollections

In various contexts, the Pali literature and Sanskrit Mahayana sutras emphasize and identify different enumerations of recollections.
Three recollections

The Three Recollections:

        Recollection of The Buddha (Pali Buddhānussati, Skt. Buddhanusmrti, Tib. Sans- rgyas -rjes-su dran pa)
        Recollection of the Dhamma (Pali Dhammānussati, Skt. Dharmanusmrti, Tib. Chos- rjes- su dran pa)
        Recollection of The Sangha (Pali Saṅghānussati, Skt. Sanghanusmrti: Tib. dge -hdun- rjes- su dran pa)

The Dhammapada declares that The Buddha's disciples who constantly practice recollection of the Three Jewels "ever awaken happily." According to the Theragatha, such a practice will lead to "the height of continual Joy."

Unlike other subjects of meditative recollection mentioned in this article, the Three Jewels are considered "devotional contemplations." The Three Jewels are listed as the first three subjects of recollection for each of the following lists as well.
Five recollections

On a Buddhist sabbath (Uposatha) day, in addition to practicing the Eight Precepts, The Buddha enjoined a disciple to engage in one or more of Five Recollections:

        Recollection of The Buddha
        Recollection of the Dhamma
        Recollection of The Sangha
        Recollection of Virtue (Sīlānussati)
        Recollection of Deva virtues (devatānussati)

According to The Buddha, for one who practices such recollections: "'his mind is calmed, and Joy arises; the defilements of his mind are abandoned.'"
Six recollections

The Six Recollections are:

        Recollection of The Buddha
        Recollection of the Dhamma
        Recollection of The Sangha
        Recollection of Generosity (cāgānussati)
        Recollection of Virtue
        Recollection of Deva virtues

The Buddha tells a disciple that the mind of one who practices these recollections "is not overcome with passion, not overcome with aversion, not overcome with Delusion. His mind heads straight, ... gains Joy connected with the Dhamma..., rapture arises..., the Body grows calm ... experiences ease..., the mind becomes concentrated."

In Mahayana practice, the first six recollections were commonly taught and The Buddha anusmriti was particularly emphasized in many popular sutras such as the Medicine Buddha Sutra.
Ten recollections

As Ten Recollections, the following are added to the Six Recollections:

        Recollection of Death (Maraṇānussati)
        Recollection of the Body (kāyagatāSati)
        Recollection of the Breath (ānāpānassati)
        Recollection of peace (upasamānussati)

In the Pali canon's Anguttara Nikaya, it is stated that the practice of any one of these ten recollections leads to Nirvana.

The Visuddhimagga identifies the Ten Recollections as useful Meditation subjects for developing Concentration needed to suppress and destroy the Five Hindrances during ones pursuit of Nibbana.

In terms of the development of meditative absorption, Mindfulness of the Breath can lead to all four jhanas, Mindfulness of the Body can lead only to the first Jhana, while the eight other recollections culminate in pre-jhanic "access Concentration" (upacara Samadhi).
Specific subjects of recollection

As indicated in the above sets, the following are recollected subjects of either Meditation or devotion.
Recollection of The Buddha

The standard formula when recollecting The Buddha is:

    Iti pi so bhagavā arahaṃ sammā-saṃbuddho vijjācaraṇasaṃpanno sugato lokavidū anuttaro purisadammasārathī satthā devamanussānaṃ buddho bhagavā ti

    'Indeed, the Blessed One is worthy and rightly self-awakened, consummate in Knowledge & conduct, well-gone, an expert with regard to the World, unexcelled as a trainer for those people fit to be tamed, the Teacher of divine & human beings, awakened, blessed.'

It has been suggested that the Recollection of The Buddha identified in the Theravada canon might have been the basis for the more elaborately visual contemplations typical of Tibetan Buddhism.
Recollection of the Dhamma

The standard formula when recollecting the Dhamma is:

    'The Dhamma is well-expounded by the Blessed One, to be seen here & now, timeless, inviting verification, pertinent, to be realized by the wise for themselves.'

Recollection of The Sangha

The standard formula when recollecting The Sangha is:

    'The Sangha of the Blessed One's disciples who have practiced well... who have practiced straight-forwardly... who have practiced methodically... who have practiced masterfully — in other words, the four types [of noble disciples] when taken as pairs, the eight when taken as individual types — they are The Sangha of the Blessed One's disciples: worthy of gifts, worthy of Hospitality, worthy of offerings, worthy of respect, the incomparable field of Merit for the World.'

Recollection of actual past lives

For one accomplished in meditative Concentration, there is the possibility of attaining the recollection of one's own past lives (pubbenivāsānussati). In this case, anussati is not a meditative subject to achieve jhanic absorption or devotional bliss; it is the actual fruit of practice.

An example of one who has achieved such a Power is described in the following manner by The Buddha in the "Lohicca Sutta" (DN 12):

    "With his mind thus concentrated, purified, & bright, unblemished, free from defects, pliant, malleable, steady, & attained to imperturbability, he directs & inclines it to Knowledge of the recollection of past lives (lit: previous homes). He recollects his manifold past lives, i.e., one birth, two births, three births, four, five, ten, twenty, thirty, forty, fifty, one hundred, one thousand, one hundred thousand, many aeons of cosmic contraction, many aeons of cosmic expansion, many aeons of cosmic contraction & expansion, [recollecting], 'There I had such a name, belonged to such a clan, had such an appearance. Such was my Food, such my experience of pleasure & pain, such the end of my Life. Passing away from that state, I re-arose there. There too I had such a name, belonged to such a clan, had such an appearance. Such was my Food, such my experience of pleasure & pain, such the end of my Life. Passing away from that state, I re-arose here.' Thus he recollects his manifold past lives in their modes & details...."

Source

Wikipedia:Anussati