The Contemplation Sutra sets out sixteen visualisations, beginning with the setting sun and building through the ground, the trees, the water and the ornaments of the Pure Land to the figure of Amitabha himself. Read straightforwardly, it prescribes a demanding programme of sustained visual concentration, and most earlier commentators read it that way, treating the final passages about simply calling the Buddha's name as a concession to the incapable.
Shandao inverted the emphasis. He argued that the sutra's intended audience is precisely the ordinary, distracted, morally compromised person, that the visualisations describe what the Pure Land is rather than prescribe how to reach it, and that the practice actually enjoined is the vocal recitation of the name. He distinguished the right and settled practice, recitation, from the supporting practices of reading, contemplation, worship and praise, and he grounded the whole on Amitabha's vow rather than on any quality of the practitioner. Merit accumulated by the practitioner is not what carries them; the vow is.
He also read the sutra's nine grades of birth as covering people who had committed the gravest offences, which mattered enormously to those who received it. The Pure Land became not a reward for the accomplished but a refuge for those with nothing to offer, and the practice became something a person could do while working.