If a competition were held to select the most popular sutra in Buddhism, the following sutras would very likely be among those nominated:
The Heart Sutra. Probably the most well-known and influential sutra, the Heart Sutra is in fact an extract from the Mahaprajnaparamita Sutra, the longest of all the sutras. It was spoken by the Buddha to his disciples, but was specifically directed at Shariputra, one of his two foremost male disciples alongside Maudgalyayana. It summarizes the basic yet profound concept of emptiness, from which are derived the Three Universal Truths of Buddhism—anitya, that all phenomena are impermanent; anatman, that there is no such thing as self; and duhkha, that all phenomena are unsatisfactory.
The Sutra of the Causal Vow of the Bodhisattva Kshitigarbha. The most fundamental sutra for newcomers to Mahayana Buddhism, it was spoken by the Buddha in the Trayastrimsha Heaven for his deceased mother after he entered nirvana. It is also known as the “sutra of filial piety,” because filial piety is the most basic moral code that all Buddhists should live by. In the sutra, Shakyamuni Buddha assigned the bodhisattva Kshitigarbha to act on his behalf and take care of sentient beings in our Saha World of suffering until the bodhisattva Maitreya descends from Tushita Heaven to attain Buddhahood in this world. The beginning of this sutra describes fantastic displays of light and clouds, with a multitude of sagely beings—all of which make it unusually grand and dramatic.
The Avatamsaka Sutra. This is sometimes known as the “encyclopedia of Buddhism” because it reveals the splendid and mysterious realm of the Buddhas. Shakyamuni Buddha uttered this sutra to all the sages in heaven and on earth soon after he attained Buddhahood. The sutra tells the histories, achievements, and cultivation methods of the many great bodhisattvas. Unfortunately, ordinary beings are unable to understand its profound teachings.
The Lotus Sutra. Known as the “king of sutras,” the Lotus Sutra was spoken by the Buddha to his disciples during his last decade in this world before entering nirvana. It concludes all the teachings given by Shakyamuni Buddha during the 49 years of his teaching life and encourages his disciples to pursue Buddhahood and not to dwell indefinitely in the state of arhatship (the ultimate goal of shravakas [hearers of the teachings] and pratyekabuddhas [solitary realizers]). However, the ultimate teaching of the One Buddha Vehicle* was not easily believed or accepted by practitioners of the Two Vehicles (shravakas and pratyekabuddhas), and 5,000 monks left the assembly before the Buddha spoke the sutra.
The Agama Sutras. These are the original and universally venerated teachings of Shakyamuni Buddha from the beginning of his teaching life, when he spoke to his disciples about how they should liberate themselves from suffering. These sutras are the most practical and the most directly relatable to our daily lives.
The Amitabha Sutra. One of the three Pure Land sutras, it is the shortest and most popular for Pure Land devotees to study and recite. Recitation of the Amitabha Sutra is considered by many Mahayana Buddhists, particularly Pure Land practitioners, to be an essential practice.
There are, of course, many other popular and influential sutras, such as the Diamond Sutra and the Shurangama Sutra. Indeed, all sutras represent different aspects of the truth that we should heed. However, Master Shandao, the de facto founder of Pure Land Buddhism, said in his Commentary on the Contemplation Sutra that there were important differences when Shakyamuni Buddha taught a particular sutra, in terms of location, time, and audience, and in the benefits each particular audience would derive. In this respect, I believe the Contemplation Sutra deserves to be nominated as the “most unusual sutra”:
1. Difference in location: most sutras were spoken in Dharma assembly places, such as Mrigadava, or Sarnath; Kalandaka Venuvana, or the Bamboo Grove; Jetavana; Gridhrakuta, or Vulture Peak; in the heavens, and so on. However, the Contemplation Sutra is very unusual in that Shakyamuni Buddha taught it in the prison of the palace of King Bimbisara, who ruled India from 544–492 BCE. The location is therefore exceptional.
2. Difference in time: this sutra was spoken at the same time that Shakyamuni Buddha delivered the Lotus Sutra at Vulture Peak. Queen Vaidehi, who had been imprisoned by her son Prince Ajatasatru, was in such a desperate situation that she was almost ready to die and wished to know how to attain rebirth in a better world. Shakyamuni Buddha “split” his body and visited the prison, where he taught her the Contemplation Sutra. The timing of the teaching of this sutra is therefore crucial.
3. Difference in audience: most sutras were spoken before a multitude of the Buddha’s disciples, as well as the great bodhisattvas of the ten directions. However, when the Buddha taught the Contemplation Sutra, notably there were only three people present: Queen Vaidehi, and the Buddha’s disciples Ananda and Maudgalyayana.
In the sutra, Shakyamuni Buddha emphasized to Queen Vaidehi several times that it was spoken specifically to her—and also intended for sentient beings living in the ages after the Buddha attained nirvana (especially during the Era of Dharma Decline, the present age of Buddhism). The entire sutra was then repeated by Ananda after he returned to the assembly at Vulture Peak.
4. Difference in benefit: with the guidance of Shakyamuni Buddha, Queen Vaidehi chose to be reborn in the Land of Bliss. This sutra was therefore taught for those wishing to be reborn in Amitabha’s Pure Land. Shakyamuni Buddha first elucidated the various practices by which it is possible to attain rebirth there, and then concluded the sutra by advising us to practice Amitabha-recitation. Once reborn in the Pure Land, sentient beings are liberated from the cycle of reincarnation, attain a state of non-retrogression, and expedite the achievement of Perfect Enlightenment. This benefit is therefore exceptionally great.
The Contemplation Sutra is perhaps the only sutra spoken by Shakyamuni Buddha to ordinary beings. It was specifically intended for iniquitous beings in the Saha World, like ourselves, who seek ultimate happiness and liberation from the cycle of reincarnation in the Era of Dharma Decline.
Unfortunately, the Contemplation Sutra is neglected by many Buddhists, including Pure Land practitioners. Master Shandao chose this unusual sutra as the subject of his commentary when he established the Pure Land school of Buddhism during the Tang dynasty (618–907). It is truly wonderful that Master Shandao explained the hidden meaning of this sutra and revealed Shakyamuni’s important message, providing an opportunity to know the way to ultimate liberation.
* The Lotus Sutra states that the three vehicles of the shravaka , pratyekabuddha [both leading to arhatship], and bodhisattva [leading to full Buddhahood] are actually just expedient devices for attracting beings to the One Buddha Vehicle, via which they all become Buddhas. Buddhahood is considered a higher state of realization than arhatship.