More on Actual and Theoretical Ichinen Sanzen

In the Latter Day Actual Ichinen Sanzen is Namu Myoho renge kyo and Gohonzon and 3000 Worlds in a Moment of Life is Theoretical Ichinen Sanzen.

Theoretical Ichinen Sanzen:

Three Thousand Realms (or Worlds) In a Momentary Existence of Life 

Each of the Ten Realms [Hell, Hunger, Animality, Anger, Humanity, Rapture, Learning, Self Realization, Bodhisattva, and Buddha] is manifest from moment to moment and contains Ten Realms which are latent. This makes One Hundred Realms. Each of the One Hundred Realm contains Ten Factors (appearance, nature, entity, power, influence, internal cause, relation, latent effect, manifest effect, and their consistency from beginning to end). This makes One Thousand Realms. Each Realm also contains the Three Principles of Individuation [the Realm of the Individual, the Realm of the Society of Beings and the Realm of the Environment. This makes Three Thousand Realms. 

In general, a Bodhisattva [selfless being] manifests primarily Bodhisattva from moment to moment and always quickly returns to Bodhisattva when manifesting one of the other realms. The Bodhisattva has the Appearance, Nature, Entity, Power, Influence, Cause, Condition, Latent Effect, Manifest Effect, and Consistency from Beginning to End of a Bodhisattva. Both the society or collection of beings in which the Bodhisattva resides and the environment [land] of the Bodhisattva manifest predominantly the Realm of Bodhisattva. 

In general, a cat manifests primarily Animality from moment to moment and always quickly returns to Animality when manifesting one of the other realms. The cat has the Appearance, Nature, Entity, Power, Influence, Cause, Condition, Latent Effect, Manifest Effect, and Consistency from Beginning to End of an animal. Both the society or collection of beings in which the cat resides and the environment of the cat manifest predominantly the Realm of Animality. 

A Bodhisattva will manifest Animality for periods of time when, for example, he experiences the urge to sleep or defecate. A cat will manifest Bodhisattva for periods of time when, for example, it acts selflessly towards its kittens or its owner. 

Tientai asserted that every being has the potential to elevate its central life tendency [or the Realm or Realms to which it gravitates] through the principle of Ichinen Sanzen. For example, a cat can create the causes and conditions for Bodhisattva by either very strongly [for a moment] or habitually acting selflessly. Intent, according to Tientai, is far less important than actuality or suchness in elevating [or lowering] one's central life tendency. 

The practice advocated by Tientai was meditation directed towards perceiving the Three Thousand Realms In a Momentary Existence of Life. He recited the title of the Lotus Sutra ten thousand times a day for his personal practice but since the time and the people's capacity were not ripe for the widespread propagation of the principle practice of the Lotus Sutra, he refrained from advocating this practice for others. 

Actual Ichinen Sanzen:

Nichiren Daishonin taught Actual Ichinen Sanzen or one moment of exceptionally profound faith and joy in Namu Myoho renge kyo and its continuous recollection is itself Buddhahood.