Zhiyi taught that the four doctrinal teachings were combined like ingredients into five different flavors of Dharma. The perfect teaching by itself was the best, but other flavors and periods made concessions to those who were not ready for the perfect teaching by combining it with other teachings, or in the case of the Deer Park period excluding it altogether. While Zhiyi believed that the Buddha used these different flavors throughout his fifty years of teaching, he also indicated that certain sūtras exemplified particular flavors. The seventh century Tiantai patriarch and reformer Zhanran later identified these flavors and their corresponding sutras more rigidly with a chronological scheme of the Buddha’s teachings called the five periods. In Treatise on protecting the Nation, Nichiren provides citations from various sūtras to justify this time scheme of the five periods. These five flavors or periods were then made to correspond to certain analogies used in the sūtras. One analogy comes from the Nirvāṇa Sūtra and relates the teachings to milk and its products – cream, curds, butter, and clarified butter. This analogy was Zhiyi’s inspiration for the five flavors. Another analogy relates the teachings to the process by which an estranged son is reconciled with his father and given his birthright as related in the parable of wealthy man and his poor son in the fourth chapter of the Lotus Sūtra. Yet another analogy comes from the Flower Garland Sūtra and relates the teachings to the progression of the sun from dawn to high noon.

1. The Flower Garland – This lasted for the first three weeks after the Buddha’s awakening and as such was not perceived by anyone but the gods and advanced bodhisattvas. This period combines the perfect teaching with the specific teaching. This means that while the Flower Garland Sūtra presents the final goal of Buddhism, many parts are aimed only at the bodhisattvas and so exclude those who do not share their aspirations or insight. This period is compared to fresh milk before it undergoes any further refinement; or to the time when the prodigal son is frightened to death by the magnificent wealth and power of the father whom he has forgotten; or the sun at dawn that illuminates only the highest peaks of the mountains.
2. The Deer Park – for the next twelve years beginning with the Deer Park discourse, the Buddha exclusively taught the tripiṭaka doctrine for the śrāvakas. At this stage the Buddha taught the four noble truths and the twelvefold chain of dependent origination in order to free people from worldly attachments and to overcome self-centeredness. This period is compared to the cream derived from milk; or the time when the father sends servants to employ the son for menial labor and later visits the son dressed as a fellow worker; or the sun when it has risen high enough to illuminate the deepest valleys.
3. The Expanded (Vaipulya) – for the next eight years the Buddha taught preliminary Mahāyāna teachings in order to castigate the śrāvakas for their complacency and to inspire the novice bodhisattvas by teaching the six perfections, the emptiness of all phenomena, and the existence of the buddhas in the pure lands of the ten directions. The Vimalakirti Sūtra, the three Pure Land sūtras, and those pertaining to Consciousness-Only and later the esoteric teachings are all lumped into this catch-all category which contains all four teachings by content that are taught depending on how they correspond to the needs of the audience at any given time and place. This period is compared to the production of curds; or the time when the son and the father develop mutual trust and the son enters his father’s mansion freely on business; or the sun at breakfast time.
4. The Prajña or Perfection of Wisdom (Prajña-pāramitā) – for the next twenty-two years the Buddha taught the Perfection of Wisdom sūtras which included the common, specific and perfect teachings, but not the tripiṭaka teachings. This period emphasized the emptiness of all phenomena and negated all the distinctions and dichotomies set up in the previous teachings so the way would be clear for the Buddha’s ultimate teaching in the following period. This period is compared to the production of butter; or the time when the father entrusts the son with his storehouses of gold, silver, and other treasures; or the sun late in the morning.
5. The Lotus and Nirvāṇa – in the last eight years of the Buddha’s life he taught only the unadulterated pure teaching in the Lotus Sūtra and reiterated it in the Nirvāṇa Sūtra. This was the period which not only comes full circle back to the Buddha’s own point of view but brings along all those who were gradually prepared by the last three periods and who did not understand or felt left out of the sudden teaching of the Flower Garland period. In this teaching the eventual attainment of buddhahood by all beings and the timeless nature of the Buddha’s awakening are affirmed. This period is compared to the production of clarified butter or ghee; the time when the father reveals that he is the son’s true father and bestows all his wealth upon the son; or the sun at high noon.