The Zen concept 'Makyo' or 'Makkyo' is often translated into English as either the "ghost cave" or "devil's cave." It is meant to refer to a chimera, illusion or hallucination, which is believed to lead to a demonic state or region. The term, 'makyo' is Japanese. It is written in Kanji as two characters. The first of these (Jap) 'ma' is understood to mean "demon, devil or evil spirit," which is the sense of this character when it is taken as an independent word in Japanese. It is synonymous with akuma (aku+ma). The Chinese version of this concept is 'mo-jing.' In Chinese 'mo' means 'demon,' much like 'ma' does in Japanese. It should be noted that this character 'mo' is a character that was also used in the translation of the Pali term 'Mara'. If you recall 'Mara' is the "evil one" in early Buddhist literature. Thus things that are 'mo-jing' or 'makyo' are of or relating to 'Mara' who leads us away from enlightenment, and is thus evil,
The term 'mo-jing,' 'makyo' or 'makkyo' is most often in reference to seated meditation with one's eyes closed. In Ch'an, Son and Zen meditation with the eyes closed is not considered the preferred method because they believe when one's eyes are closed it is too easy to be drawn into hallucinations without the material world being present as a reference point to discriminate the illusive from the real.
The point however, is not whether the eyes should be open or closed during meditation, which this contemplative believes is purely a cultural and personal one, however, the issue is that the phenomena of meditative absorption is also often called 'mo-jing,' 'makyo' or 'makkyo' within a Ch'an, Son or Zen context. It is this conflation of the phenomena of meditative absorption (Jhana-Nimitta) with evil that is typical of how religions, even Buddhist ones, demonize gnosis. And, this is the reason why this contemplative points to the concept behind the terms 'mo-jing,' 'makyo' or 'makkyo' as evidence that Ch'an, Son and Zen may very well have lost the art of meditative absorption (jhana).
In support of this premise we can also look to the literature of Ch'an, Son and Zen and find little reference to the meditative absorption states other than in the Dogen Zen JI. If there is no dialog on or about the meditative absorption states (jhanas) within a contemplative tradition, then it seems reasonable to say that contemplative tradition has lost the art of meditative absorption (jhana).
While I have a great deal of respect for all contemplative traditions, especially the various Zen schools, it does not appear that any of them practice "sensitive" to a pleasant abiding (jhana). This is very unfortunate, especially when one considers that the Japanese term 'Zen' came from the Korean term 'Son', which came from the Chinese term 'Ch'an' which came from the Sanskrit term 'dhyana' which came from the Pali term 'jhana'. So, it appears only the word arrived in Northern Asia from China to Japan, through five layers of interpretation, not its meaning.
The loss of the ecstatic meaning from Jhana to Zen may be due in part to the many layers of translation and interpretation that the Buddha dhamma had to go through to get to Japan. However, if we consider how the Buddha's discourses were exported to the rest of Asia we may find a clear source of the origin of how the ecstatic component of the Buddha's message was left out in most Mahayanist literature.
If you recall the non-Theravadan Buddhist schools look to a Sanskrit translation of the Buddha's discourses instead of the Pali version. There are no doubt many differences in the Sanskrit translation that do not reflect the Pali version of the suttas/sutras. The most relevant to our point here is in the translation of the Pali term 'jhana' into the Sanskrit term 'dhyana.'
If you are familiar with the Yoga Sutras of Patanjali, then you will know that the Sanskrit term 'dhyana' is not related to the term 'samadhi.' In the Yoga Sutras, 'dhyana' is the practice of meditation techniques, through which one arrives at meditative absorption (samadhi). Thus the term 'dhyana' is closest to how the Buddha used the term 'sati' which is the cultivation of concentration, through various cognitive techniques, leading to absorption (samadhi). Thus in the first century BC translation of the Sutta Pitaka to Sanskrit the ecstatic component of the Buddha's message was simply extracted via a bad translation, that has been compounded by 2 millennia of erroneous dogma.
We can also look at the practice method of Zen to see how it is constructed to avoid the meditative absorption states (jhanas). Most Zen meditation practice is expressed in the form of a 20 to 30 minute sit followed by a vigorous and regimented walking "meditation." The problem with this strategy is most people who have experience with meditative absorption states (jhanas) find that meditation sits of an hour or more are required for the subjective states of absorption to emerge. Thus the Ch'an, Son and Zen practice of the short sit duration may have been intentionally constructed to avoid the meditative absorption states.
The question that begs now to be answered is: Why would Ch'an, Son and Zen choose to avoid the meditative absorption states? The obvious answer lies in reflecting upon other religions, such as the Abrahamic religions, which have been demonizing the absorption states for thousands of years. Many of the martyrs of the Abrahamic religions, such as Jesus and al Hallaj were essentially martyred for their ecstatic message.
In conclusion we can see how the Mahayanist Buddhist schools, such as Ch'an, Son and Zen were never given the essential instruction set of the Buddha regarding meditative absorption (jhana). We can also see how every religion has contributed to the subversion of the ecstatic message of the mystics.