Sekida's third type of samadhi, or mental state, associated with Zen is "Both man and circumstances are deprived."
(1) Man is deprived; circumstances are not deprived.
(2) Circumstances are deprived; man is not deprived.
(3) Both man and circumstances are deprived.
(4) Neither man nor circumstances are deprived.
This type of samadhi, achieved during Zen meditation, is an intensification and deepening of State #2. The difference, according to Sekida, is that the "self-reflecting action of consciousness" is lessened, even to a point where it disappears altogether.
Here's how he describes "Both man and circumstances are deprived":
"The third category is "Both man and circumstances are deprived." A discussion of this category must be preceded by an explanation of self-consciousness. I have said that consciousness functions in two ways, outwardly and inwardly. There is another important action exercised by consciousness: one that reflects upon its own thought. This kind of reflection must be distinguished from general introspection, which deals with character or behavior. When we think, 'It is fine today.' we are noting the weather, but we are not noting that we are thinking about the weather. The thought about the weather may last only a fraction of a second, and unless our next action of consciousness reflects upon it and recognizes it, our thought about the weather is allowed to pass away unnoticed. Self-consciousness appears when you notice your thought, which immediately precedes your noticing it, and you then recognize the thought as your own.
If we do not perform this noticing action we do not become aware of our thinking, and we will never know that we have been conscious at all. We may call this action of noticing our own thoughts "the reflecting action of consciousness" to distinguish it from general introspection...
Now, when one is in absolute samadhi in its most profound phase, no reflecting action of consciousness appears. This is Rinzai's third category, "Both man and circumstances are deprived." In a more shallow phase of samadhi, a reflecting action of consciousness occasionally breaks in and makes us aware of our samadhi. Such reflection comes and goes momentarily, and each time momentarily interrupts the samadhi to a slight degree. The deeper the samadhi becomes, the less frequent becomes the appearance of the reflecting action of consciousness. Ultimately the time comes when no reflection appears at all. One comes to notice nothing, feel nothing, hear nothing, see nothing. This state of mind is called "nothing." But it is not vacant emptiness. Rather is it the purest condition of your existence. It is not reflected, and nothing is directly known of it. This nothingness is "Both man and circumstances are deprived," the condition Hakuin Zenji called "the Great Death." The experience of this Great Death is no doubt not common in the ordinary practice of zazen among most Zen students. Nevertheless, if you want to attain genuine enlightenment and emancipation, you must go completely through this condition, because enlightenment can be achieved only after once shaking off our old habitual way of consciousness."
In this third type of samadhi, all disappears, even one's awareness that they are experiencing samadhi.