The most basic criteria for reaching Amitābha Buddha (Āmítuófó; 阿弥陀佛) and Medicine (Master) Buddha’s (药师佛) Pure Lands (in the West and East respectively) are similar – the Three Provisions (of profound Faith in that Buddha, sincere Aspiration to be born in that Buddha’s Pure Land, and true Practice accordingly, with mindfulness of that Buddha’s name (or mantra). These Provisions are stated in a brief form in Āmítuófó’s ‘18th Vow Of Those With Ten Thoughts All Born In My Land’ (第十八十念皆生我国愿).
As there is no clear statement in the sūtras, in terms of Medicine Buddha’s vows, to personally receive and guide (接引) those on the deathbed to reach his Pure Land, some interpret this to mean that it might be harder to reach it, with the need for more meritorious self-powered (自力) practice. Āmítuófó however, has his ’19th Vow Of Those With Diligent Cultivation All Received And Guided By Me’ (第十九勤修我皆接引愿) – to aid reach of his Pure Land. However, there is no mention in the sūtras that Medicine Buddha’s Pure Land is harder to reach.
This might be a reason why mindfulness of Āmítuófó is a relatively more popular practice – as there is the scripturally stated vow, along with clearly related teachings, of his reception and guidance to reach his Pure Land, through which all other Pure Lands, including Medicine Buddha’s Pure Land can be reached. Such ease is stated in Āmítuófó ‘9th Vow Of All Attaining Supernormal Flight [to reach immeasurable lands]’ (第九得神足飞行愿).
That said, there still might be reception and guidance by Medicine Buddha, as Śākyamuni Buddha taught that it will take more than a kalpa to fully speak of his vows and meritorious virtues. Also, according to ‘Śūraṅgama Sūtra’s Section On Great Power Arrived Bodhisattva’s Perfect Penetration With Mindfulness Of Buddha’《楞严经大势至菩萨念佛圆通章》, this was taught – ‘If sentient beings’ minds recollect [a] Buddha, [or are] mindful [of that] Buddha, manifesting in the present [or in the] future, [they will] definitely see [the] Buddha.’ (若众生心，忆佛念佛，现前当来，必定见佛。) However, again, Medicine Buddha’s reception and guidance for those departing from life is not stated explicitly.
Incidentally, the Medicine Master Sūtra《药师经》states that Āmítuófó’s Pure Land and Medicine Buddha’s Pure Land have ‘meritorious virtues’ adornments equal without difference’ (功德庄严，等无差别). This makes the issue of which Pure Land being easier to enter all the more crucial, as a deciding factor of which to reach first. It should be noted that mindfulness of ‘Medicine Master Lapis Lazuli Light Thus Come One’ [(南无)药师琉璃光如来] takes more time than ‘Āmítuófó’ [(南无)阿弥陀佛] in terms of their names.
If Medicine Buddha’s Pure Land is looked forward to, mainly for healing of body and/or mind, the truth is that sincere mindfulness of either Āmítuófó or Medicine Buddha’s name (or mantra) will both work for this purpose now – partially if the negative karma involved is much, and fully with lasting healing for sure, upon reaching their Pure Lands.
Medicine Buddha And Amitābha Buddha’s Connection
Or one can simply first be born in Amitabha Buddha’s Pure Land and can go visit Medicine Buddha’s Pure Land, or even send a transformation body always in that land.
All Buddhas are fundamentally the same body and mind after the attainment of wonderful Bodhi. They manifest themselves according to their former Bodhisattva vows and aspirations of sentient beings in pure and defiled lands according to the karma of sentient beings.
… seeing Amitabha Buddha is equal to seeing the Buddha Tathagathas of 10 directions.