Question: Is it a must to practise any of the contemplations that involve visualisation, as stated in the Contemplation Sutra (观经)?
Answer: Since very early days, as far back as that of the Pure Land Tradition’s 2nd Patriarch Great Master Shandao’s (净土宗二祖善导大师) time and possibly even earlier, it was already taught that the visualisation (or contemplation) practices (观想念佛) in the Contemplation Sutra are difficult to accomplish due to the sutra’s intricately refined instructions, coupled with the coarseness of ordinary beings’ minds. A mindful study of the sutra will swiftly reveal these difficulties.
As a conclusive note near the end of Great Master Shandao’s ‘Commentary On The Contemplation Sutra In Four Fascicles’ (观经四帖疏), he taught this – ‘Looking towards the Buddha’s real wish [or fundamental vows], his intention was that sentient beings, [practise] single-pointed, [sincere, constant, complete and] focused recitation, of Amituofo’s name.’ (望佛本愿，意在众生，一向专称，弥陀佛名。)
As Great Master Shandao is recognised by many as Amituofo’s manifestation, this is also a reason why subsequent Pure Land Patriarchs all advocate upholding the name of Amituofo (持名念佛) as the main practice.
Note that visualisation practice is also a standalone practice, not to be practised at the same time as the practice of upholding the name of Amituofo. This is so as constant toggling of the mind between his name and his image makes the mind not wholehearted, easily leading to scatteredness. We can clearly see too, in the three key Pure Land sutras, that upholding of the name, although relatively much simpler, will fully suffice as the main practice for reaching Pure Land.
 In the Amitabha Sutra (阿弥陀经), this main practice is stated as, to ‘faithfully [and firmly] uphold [mindfulness of] his name [Amituofo] (执持名号)’.
 In the Immeasurable Life Sutra (无量寿经), this main practice is stated in the 18th vow of Amituofo – ‘if the ten directions’ sentient beings, with utmost sincere hearts of joyful faith, desire birth in my land, even with ten mindful thoughts, [(they) will be born there]’ (十方众生，至心信乐，欲生我国，乃至十念). Note that the easiest ‘mindful thought’ is in terms of Amituofo’s name, as above.
 In the Contemplation Sutra (观经), this main practice is stated for the Low Grade’s Low Birth, though universally applicable for all grades of birth above too, as a basic and core practice – ‘Such foolish persons, when approaching life’s end, if meeting good-knowing friends, [who offer] all kinds of comforting [i.e. consolations], for them speaking the wonderful Dharma, teaching to enable them to be mindful of [Amita(bha)] Buddha, that person, if by suffering compelled, too flustered [and confused], to be mindful of Buddha [via other means], a good friend speaks these words, “If you are not able to be mindful of that Buddha, you should recite [the name of] Immeasurable Life Buddha [Amitayus Buddha; Amituofo], thus with a sincere mind, enabling its sound to not be interrupted, completing ten thoughts, of reciting ‘Namo Amituofo’ [Homage to, and refuge for life in Amituofo].”’ (如此愚人，临命终时，遇善知识，种种安慰，为说妙法，教令念佛，彼人苦逼，不遑念佛，善友告言：’汝若不能念彼佛者，应称无量寿佛，如是至心，令声不绝，具足十念，称南无阿弥陀佛。’)
Especially in the last case, such a desperate dying person will have no time to practise any visualisation at all, yet this person can still reach Pure Land with utmost sincere upholding of Amituofo’s name with the right faith and aspiration (信愿持名). It is likewise thus when assisting in all urgent support-chanting cases. To inspire those ignorant on the nature of Pure Land, so as to urge them to uphold the name of Amituofo, a quick summarised introduction of Amituofo and his Pure Land using the relatively short Amitabha Sutra as a guide will do. There is usually chanting of this sutra after death for offering more guidance too. For a visual sense of who the dying person should take refuge in, a clear image of Amituofo (as a picture or statue) for occasional glimpsing will suffice, while the main practice is still upholding of his name.
It makes great practical sense too, to ensure that we master this main practice, so as to be able to enter Pure Land, before even attempting to master much more difficult visualisation practices, which we might never be proficient in within this lifetime, thus not reaching Pure Land through them. The sutra says too, that the visualisations are to be practised in detail, step by step, with increasing difficulty, stating that ‘if with other visualisations [or contemplations], they are named as evil contemplations’ (若他观者，名为邪观), which emphasises the seriousness of contemplating wrongly. That said, it is still fruitful to study and recite the sutra, to have an impression of Pure Land’s excellent features, so as to further inspire us to joyfully aspire to reach it. These features are also described in other ways in the other two Pure Land sutras and beyond.
The Pure Land Tradition’s 13th Patriarch Great Master Yinguang (净土宗十三祖印光大师) also taught that the main practice of upholding the name of Amituofo is the most appropriate, able to lead to sight of Amituofo and his Pure Land even without any prior visualisation practice. It is thus a profound shortcut for reaching Pure Land to attain Buddhahood. He also gravely warned that practising visualisation might lead to demonic obstacles (e.g. of disturbances and hallucinations). One of his letters with teachings on these concerns can be seen at http://purelanders.com/2017/04/05/should-we-practise-visualisation-of-pure-land-amituofo