Two Forms of Sitting Meditation for Zen Students
Seiza Sitting Meditation (Mokuso)
Just sit comfortably in Seiza and still your mind. Raise some energy before you begin. As you sit your energy will rise even more, but be alert and relaxed so it rises in a non-abrupt way. Breathe in through your nostrils, out through your mouth. Let the in-breathing sink down to the very bottom, like a broken tile tossed into a deep pond, before it rises. Gaze with eyes unfocused at the expanse before you without fixing on any single point, or shut your eyes if you prefer. But if you do shut your eyes, be careful not to focus on any mental images or thoughts that might appear. Regard them as like soap bubbles or flashes of lightning. Do not chase any thoughts and do not develop one thought from out of another. Cast away the bitter dregs of the past and all hopes or longings for the future. Abide in the natural brightness & clarity before there is any constructed thinking or particular intention. Forget everything but This, which is the simple, profound, inconceivable state of all the sages and Buddhas.
Tibetan Zen Sitting (Lotus or Half-Lotus)
"Cross your hands and feet. Straighten your back. Don’t move your body. Don’t say anything. Turn away without engaging the delusory six gates of the mind with their objects, and then look at your own mind. When you do, there is no substantiality to mind at all. So do not think of anything. Without engaging in the various emotional states, do not conceptualize anything. Once you have completely purified the mental sphere in this way, do not abide anywhere. Once you have sat for a long time, the mind will stabilize." -from Tibetan Zen