TL;DR: The twelve nidanas (thập nhị nhân duyên) are twelve linked stages running from ignorance, mental formations and consciousness through to birth, old age and death, in which each one conditions the next. This chain explains why sentient beings keep repeating the cycle of birth and death, and the Buddha taught that cutting a single link, typically craving or ignorance, brings samsara to an end. This is a foundational teaching of Theravada Buddhism, presented by Trần Trọng Kim in Phật lục (1940) and Phật giáo (1958).
What Are the Twelve Links of Dependent Origination?
The twelve links of dependent origination, also called thập nhị nhân duyên, are twelve links describing how beings endlessly arise and pass away in rebirth. Each link is both the result of the previous link and a condition for the next, so the chain does not break but turns in a circle. Trần Trọng Kim in Phật lục (1940) placed this teaching on par with the Four Noble Truths when he said the original core of Shakyamuni's teaching lay in two parts: the Four Noble Truths and the twelve links of dependent origination[1].
He explained that nhân is the seed and duyên is the cord, and that the twelve segments are interwoven like a chain: one segment, through conditions, produces the next as its fruit, and that fruit in turn, through conditions, becomes the cause of the following segment[2]. The image he used is seawater stirred into waves by wind: waves rise and sink, sink and rise, never resting[2].
It should be said clearly at once: the list of twelve links below matches the Pali discourse SN 12.2[3], while Trần Trọng Kim's explanations are those of a popular Vietnamese work and sometimes differ from the definitions in the discourses. Other traditions may emphasize different aspects. Where the schools do not agree, the article will say so.
What Are the Twelve Links?
The list of twelve links is recorded consistently across the sources. In Phật giáo (1958), Trần Trọng Kim lists the twelve links in order: ignorance, volitional formations, consciousness, name and form, six sense bases, contact, feeling, craving, clinging, becoming, birth, aging and death[2]. In Phật lục (1940), a few links are named differently, such as name and form, six sense bases, feeling, craving, clinging, becoming, birth, aging and death, but the order and meaning remain the same[1].
| Order | Link | Common Sino-Vietnamese name | Brief meaning |
|---|---|---|---|
| 1 | Ignorance | 無明 | Delusion, darkness from beginningless time |
| 2 | Volitional formations | 行 | Thinking and then acting, forming karma |
| 3 | Consciousness | 識 | Awareness, knowing oneself as oneself, knowing one can act |
| 4 | Name and form | 名色 | Mind and body, the mental and the material |
| 5 | Six sense bases | 六入 | The six senses: eye, ear, nose, tongue, body, mind |
| 6 | Contact | 觸 | Contact between sense and object |
| 7 | Feeling | 受 | Sensing, receiving |
| 8 | Craving | 愛 | Liking, wanting |
| 9 | Clinging | 取 | Grasping, holding tight |
| 10 | Becoming | 有 | Existing, becoming |
| 11 | Birth | 生 | Being born |
| 12 | Aging and death | 老死 | Growing old and dying |
This table is only a reference frame. The meaning of each link needs to be read together with the sections below.
Why Are the Twelve Links Called a Chain?
The name "chain" comes from the structure of the teaching. Trần Trọng Kim explained that each segment is both the fruit of the previous segment and the cause of the next, so the twelve segments do not stand apart but are interwoven[2]. He also distinguished nhân and duyên: nhân is the seed, duyên is the cord, that is, the condition that helps the seed sprout into fruit[2].
The phrasing in the Pali texts follows the same pattern. The familiar formula is "when this exists, that exists; when this arises, that arises; when this does not exist, that does not exist; when this ceases, that ceases." This is the principle of dependent origination, and the twelve links are one detailed presentation of that principle along the timeline of a being.
How Does Each Link Work?
Ignorance Conditions Volitional Formations
He defines ignorance as delusion, darkness from beginningless time[2]. Because of ignorance there are volitional formations. Acting after thinking is volitional formation; once one has thought and acted, karma is formed, that is, a habit, a latent tendency; and it is because of karma that action does not stop[2].
In other words, ignorance is not ordinary lack of knowledge but failure to see the true nature of things, and that failure to see drives action in the direction of creating karma.
Volitional Formations Condition Consciousness
Ignorance takes volitional formations as its fruit, and volitional formations are also the cause leading to consciousness. Trần Trọng Kim defines consciousness as awareness, as knowing, knowing oneself as oneself, knowing oneself as something that can act[2]. Here consciousness is not mere perception but awareness of a self that acts.
Consciousness Conditions Name and Form
Consciousness is the fruit of volitional formations and the cause of name and form. Name and form are mind and body, the mental and material parts of a being. In the Pali discourse SN 12.2, name consists of feeling, perception, intention, contact, and application of mind, and form is the four principal states and the form derived from them[3].
Name and Form Condition the Six Sense Bases
Name and form condition the six sense bases, that is, the six sense bases. The six sense fields in SN 12.2 are the eye, ear, nose, tongue, body, and mind[3].
The Six Sense Bases Condition Contact
Contact is the meeting of sense and object. When there is an eye and there is a form, there is contact. In the chain, contact is the condition for feeling.
Contact Conditions Feeling
Feeling is sensing, receiving. When there is contact there is a pleasant, unpleasant, or neutral sensation. Here the chain begins to shift into the part of psychological reaction.
Feeling Conditions Craving
Craving is liking, wanting. From pleasant feeling comes liking, from liking comes clinging. This is the link usually emphasized in practice, because it is where intervention is possible.
Craving Conditions Clinging
Clinging is grasping, holding tight. Craving strengthens into clinging, that is, not only liking but wanting to keep, wanting to possess.
Clinging Conditions Becoming
Becoming is existing, becoming. Clinging leads to new action that creates karma, and that karma leads to a new life.
Becoming Conditions Birth
Birth is being born. When there is karmic becoming, there is birth.
Birth Conditions Aging and Death
Birth leads to aging and death. Trần Trọng Kim writes: to have no aging and death, one must cut the condition of birth; to have no birth, one must cut the condition of becoming[1].
Where Is the Chain Cut?
This question is the heart of practice. Trần Trọng Kim writes in Phật lục that one should keep cutting in this way back through the condition of consciousness, of volitional formations, and of ignorance, and one will be liberated from rebirth[1]. He also stressed that liberation from rebirth, no longer being born or dying, is the great aim of Buddhism[1].
So there are two ways of speaking about where to cut. One way cuts at the root, that is, ignorance. Another way cuts in the middle, that is, craving and clinging. Different traditions emphasize different points.
How Do the Twelve Links Differ from the Four Noble Truths?
The two teachings are closely related but not identical. Trần Trọng Kim in Phật lục (1940) placed the two teachings side by side when speaking of the original core of Buddhism[1]. The Four Noble Truths are the truth of suffering, the truth of the cause of suffering, the truth of the cessation of suffering, and the truth of the path leading to the cessation of suffering[1]. The twelve links go into the detail of the truth of the cause of suffering, that is, they explain the mechanism by which suffering arises and continues.
In other words, the Four Noble Truths are the diagnostic frame, while the twelve links are the analysis of the mechanism of the disease. In the Pali texts, the Four Noble Truths are presented in many foundational discourses, such as the Turning of the Wheel of Dharma (SN 56.11) and the Analysis of the Truths (MN 141).
Do the Twelve Links Only Describe One Lifetime?
This is where the schools do not agree. One understanding holds that the twelve links describe three lifetimes: ignorance and volitional formations belong to the previous life, consciousness through becoming belong to this life, and birth and aging and death belong to the next life. Another understanding holds that the chain describes a single psychological moment, that is, in each instant, ignorance gives rise to volitional formations, volitional formations give rise to consciousness, and so on. Both understandings have support in the commentarial tradition, and this article does not choose one as standard.
What matters is that whether understood by lifetime or by instant, the causal structure remains the same: when this exists, that exists; when this ceases, that ceases.
How Should Readers Today Understand the Twelve Links?
Gợi ý của Nhật Nguyệt: the twelve links are not a list to memorize but a map showing where to intervene. For people living ordinary lives, the most visible point is craving and clinging: one likes something, then wants to keep it, then acts to keep it, then binds oneself to the result of that action. Seeing that circle in a specific situation, such as a relationship, a job, a habit, is already a first step. As for cutting the chain completely, according to the teaching itself, that is a matter of long practice, not of a few reflections.
It should also be said clearly: the Pali texts and academic translations only prove that the teaching was taught and recorded in this way. They do not prove that the chain of dependent origination operates like a measurable physical mechanism. This is the teaching of a religious tradition, and readers should receive it as such.
