Question: Is it ok for a nembutsu devotee to also practice various Buddhist or non-Buddhist meditation techniques and mantras, as a mean to calm one's mind or because of various positive effects these might have in one's daily life?
Answer: NO, it is not ok.
Your mind will never be calm – please learn to live with this. Life as an unenlightened person is hard, and there is nothing you can do to change this. So, just say the nembutsu of faith in Amida and wish to be born in His Pure Land after death. If you want to busy your mind with something until you die, then say nembutsu as often as possible; say it many times and concentrate on it. Sometimes your mind might become calmer if you focus on nembutsu, even if calming the mind is not the goal of nembutsu.
When we have this precious gift given by Amida Buddha to us, this unparalleled gift, this supreme gift, why mix it with anything else, why think it is not enough and why running here and there to various practices? So just say the nembutsu of faith and let your changing mind be a changing mind, let the thoughts come and go, let your karma be as it is, let there be life and let there be death. In short, be as you are; when you are well, say the nembutsu; when you feel bad, or alone, or afraid, say the nembutsu. Take refuge in Amida Buddha anytime, any place, or in whatever state of mind you are! This is my heart advice. Do not distance yourself away from Amida because you feel good or bad, but always think on His presence and rely on Him.
Of course, if your body is ill, take whatever medicine available, lets say that you may use some breathing techniques or mental and physical relaxation exercises which does not contain any spiritual or religious elements, but in spiritual and religious matters, say the nembutsu of faith exclusively. Do not resort to any other spiritual and religious help/assistance/practice from inside or outside of the Buddha Dharma, no matter what promises the proponents of these practices are given to you. Various spiritual practices from inside or outside the Buddha Dharma contain specific mental states or mental attitudes that one needs to cultivate in order to reach a certain mundane or supra-mundane goal, but if you wish to be in agreement with the Primal Vow of Amida Buddha, then do not busy yourself with anything that is not exclusively related with saying the Name in faith and aspiring to be born in the Pure Land.
But if one is busy with praying to gods or doing various mantras to feel good (which automatically relate him with other mundane or supramundane beings which are masters of those mantras) or doing meditations that imply cultivation of a certain spiritual and religious attitude of mind which is not that of reliance on Amida or saying Amida’s Name, or which imply directly or indirectly a relation with (or even faith in) various mundane or supramundane forces, then this might distance oneself from the Primal Vow. And I can never know how well established in shinjin one is, so as not to be led astray from the Path by spending too much time concentrating his mind not on nembutsu, but on various practices…
The mind of people is like a monkey and always jumps here and there inventing reasons for doing so. And especially it does not accept its mortality, so is always looking for ways to escape from it or prolonging life by spiritual/religious means. But let us remember that Master T’an Luan of our tradition burned his Taoist texts which contained meditations and various methods for permanent health and long life, when he converted to the Pure Land teachings. This should make us think …
Also, why not cultivating the attitude of Honen Shonin implied in this passage:
„The burden of one’s karma is lessened by the compassionate power of Buddha Amida for those who are faithful in nembutsu. This is called a ‘burden is lessened’. [..] Whatever illness befalls the nembutsu devotee, that misfortune is the result of residual karma. He should think that although he was supposed to receive a heavy burden, the compassionate power of Buddha Amida lessened the burden. Buddha Amida eliminates our burden of evil karma and enables us to attain birth in the Land of Ultimate Bliss, the great religious goal. There is no reason not to believe that Buddha Amida can prolong our short life and lessen our illness in daily life.”
So, let’s be aware that we suffer because of our karma, let’s go to doctors and take whatever medicine necessary, but at the mind/heart (spiritual and religious) level, always continue in the nembutsu of faith, for our burden will be lessen as much as possible by Amida Buddha if we rely exclusively on him. When they themselves were ill or when their followers were ill, our Masters (Honen, Shinan, Rennyo, etc) never recommended that the devotee do meditations or other techniques, but continue to rely on Amida. The did not accept any other spiritual or religious medicine, except the medicine of nembutsu.