‘Beginners in zazen usually find their minds confused and disturbed. This is natural. There are two great obstacles to zazen. The first is konjin, which means depression or a kind of melancholy. When a beginner experiences konjin, it is usually in the form of sleepiness.
Experienced sitters who have calmed and quieted their minds sometimes feel faint. And if the zazen condition deepens more, the sitter may fall into muso-jo or “no consciousness.” Some people believe that the zazen mind is simply loss of consciousness; however, this is wrong. In the right zazen mind, all aspects of consciousness do not function, but this does not mean unconsciousness as in sleep. The mind condition in zazen is called “shonen sozoku,” or the “succession of right-mindedness.” This is different from the “no-mindedness” which implies no consciousness. It is a good thing to calm the waves of the mind; however, a sleepy or dead condition, is a kind of konjin.
Some people feel they are in a deep fog or melancholy. One must rid one’s self of such mental conditions.
The second obstacle to zazen is called joko. For beginners this means to be in a fidget with many thoughts or ideas running through the mind. There are two types of mind waves: the first, ideas created by oneself from inside; the second, those which come from outside through the senses. Those who have experience in zazen may feel great elation; they may jump up from their cushions believing they have attained en-lightenment. This can result from sitting intently in the wrong way. Or, they may see the great light of the Buddha and feel grateful and ecstatic. Such experiences are serious obstacles; they must be overcome as quickly as possible.
These conditions are sometimes thought to be enlightenment; however, they are the result of bodily or mental fatigue or of a misunderstanding of the meaning of zazen. When zazen has deepened, one may feel bursts of great joy. The real satori is called “the mind of great joy.”
This joy, however, emanates from the mind which has transcended all relative joys as well as sorrows. Therefore we must not try to grasp these small joys; we must go beyond them, no matter how difficult and undesirable this may seem.’ (The Way of Zazen)