When each of the ten realms is multiplied by the ten realms again due to the mutual possession of the ten realms one arrives at a hundred realms. Since each of the hundred realms has ten suchnesses there are said to be one thousand realms. In addition to all this, Zhiyi taught that there are three categories of existence that must be taken into account. These categories are the five aggregates (form, feeling, perception, mental formations, and consciousness); the sentient beings of the ten realms; and the environments in which they live. These three categories show that the one thousand realms are present in and manifest themselves in terms of the components of each beings, the sentient beings themselves as a whole, and the environments inhabited by them. The one thousand realms multiplied by the three categories brings the final total up to three thousand realms that are operative in every single thought-moment.

The single thought-moment is nothing other than each singular moment of conscious awareness that comprises the here and now of our life. Each moment of awareness contains all three thousand realms. The single thought-moment and the three thousand realms arise simultaneously. There is never a single moment of awareness without all the realms present within and all the realms are always united in a single moment of awareness. In support of this