Shikantaza is the practice of doing each activity in our life for the sake of that activity, regardless of whether we are sitting, lying, walking, or standing, or working. However, this term has been used mainly with regards to zazen (meditation). It is the ultimate stage of meditation in the school of Soto Zen. It means that when we are sitting down to meditate, we are wholeheartedly sitting down to meditate and not working out our problems. And therefore the simplified translation of Shikantaza is ‘merely sitting.’ It also means that if the aim of meditation is to empty the mind of thoughts, then that is exactly what we should do. Emptying the mind is the most difficult thing to achieve in meditation. The function of the mind is to think, and thoughts of the past, present and future will inevitably arise when we sit in a semi-lotus with our eyes shut. The busier is our day, the more thoughts we will have. As a preliminary preparation, one should have as few problems in our daily affairs as possible. That is why going into a monastery where there are hardly any daily chores and where one does not have to earn a living is the ideal.
But if one has to remain a working layman, then get a job with the least emotional outlay. In order to pacify the mind the most important philosophy to believe in is the G-plan.
One’s G-plan was fashioned and concocted before one was born (read article on G-plan). If one believes in one’s G-plan, then one will realize that there is really very little free will. And one’s G-plan will inevitably unfold relentlessly, in spite of one’s efforts to the contrary. If that is the case, there are no grounds for worry and anxiety: whatever will be will be. Believing in the G-plan goes a long way towards minimizing anxieties and worries. Look for a simple job. Then the next most important exercise is to detach oneself from everything: assets, money, position and relationships. One’s daily mantra should be: "Let go." One has to practice Shikantaza on a daily basis, as often as one is able.
Before one can start practicing Shikantaza, one should learn how to concentrate with Samatha meditation. (Read lectures on Meditation and Progressive Stages of One-pointed Concentration). Do this for six to twelve months. Then one may practice Insight Meditation (Vipassana lecture) for at least six months. So after these one to two years of preparation one can now embark on Shikantaza.
Sitting in a semi-lotus position, one should move one’s body forward, backward and sideways to relax it. Then one can either shut one’s eyes or leave them open or half-open. When the eyes are shut, there will be many thoughts. When they are open, one may be distracted by what one sees in the room. Either way, one has to achieve a state of no thoughts. Do not try to trace the beginning of a thought. The best way is to let the thoughts plough through one’s consciousness without paying attention to them. It is like staying on the roadside of a busy street watching the cars go by. Do not try to identify the make of the cars. Do not try to find out who are in the cars. One starts standing there from 6 p.m. until 4 a.m. By 4 a.m. there will be either very few cars passing or no cars at all. Use the same method in dealing with thoughts. Let the thoughts pass through your mind. Do not look at them or work on them, even though they maybe immediate, cogent problems. Thoughts will finally come to an end if one ignores these thoughts. This deed can be much more easily accomplished if one is totally detached from work, possessions and relationships. Stay in that position of no thoughts for as long as one can. When it becomes very steady, one can bring that emptiness down to the heart chakra. In this way, one is deepening one’s emptiness into the Void. This deepening of emptiness must be practiced intensely and relentlessly. A time will come when a breakthrough will suddenly come about. This is when body and mind have dropped away (the eradication of the ego). This is the realization of non-duality. The light has shed into the Unconsciousness of Buddha-nature. This is satori. This first satori will inevitably be weak. After this, one’s zazen practice must continue at the same pace and with the same frequency as before. The satori will gather strength at each successive episode of satori until the final one.
Now in order to complete the full Shikantaza practice, one should also practice mindfulness in every action, conversation and thought outside of formal sitting. (Read ‘Meditation in Action.’) This is the reason for wanting an environment as in a monastery. However, the same environment can be gotten if one has enough resources to stay alone in a home in order to practice there. You are behaving as a monk in your own monastery without the chores and without the interaction of other monks. The practice here is to act, or have a conversation without having any thoughts. When you are to think, just work at that problem in your mind without any other distracting thoughts. You wholeheartedly concentrate on that problem alone and nothing else. At the beginning you have to slow down a little, but when you are proficient, you can carry on at a normal pace.