In short, this quotation from the "Collective Instruction on Performance" is the essence summarized from Ye-shes-rdo-rje. "This time" means the time of sleep. The "entering-process of the three consciousnesses[r_nar:98]" means that former consciousnesses successively enter into the later consciousnesses, and at the time of the third stage of the third consciousness the mind becomes dim. "Later" implies the time after the attainment, or the "After-stage" of the Attainment. "When the forgetfulness is overcome" denotes the time when one awakes from the non-thought consciousness in the deeply slumbering state--the experience is like beholding the clear sky at dawn. During this time no other visions (or thoughts) come to pass. "If [there is] liberation [from forgetfulness Ed.], the prana arouses the essence[r_nar:99]." Before the various dreams come in sight, one should try to concentrate on the Light as long as possible. Here, the "liberation" implies the Light Samadhi; if the Samadhi becomes dim or weakened and the yogi is forced to arise from it, through the force of the (moving) prana the flowing-thoughts will also be set in motion; whereupon the dreams also take place. In case no dream whatsoever arises (at this time) the yogi should meditate on the Light without distraction as long as possible.

If the yogi is able to bring forth the Samadhi of Sleep, but not to produce the "Light" through the prana-holding-practice, he may experience the transparency and clearness in the Samadhi of Sleep, but (since it follows not the way of Light Yoga) the Three Voidnesses preceding the sleeping-stage

would never appear. Therefore, it by no means can be considered as having the qualifications and significance of the "Light of Sleep." Besides, in the Samadhi of Sleep, the qualified and plentiful experiences of the mirage, smoke, etc., preceding the First Voidness will never come into being, but only those resembling them.

One should acquaint oneself with the two different Lights of the Light of Sleep, i.e., the Light in Experience and the Light in Realization--also the thick and thin Light, or the bright and dim Light. Though many people declare that the thoughtless, lucid, and transparent Samadhi of Sleep is identical with the Light of Sleep, no sufficient reason is found for this claim.

This exposition, based upon the teaching of the "Holy Father and Son" [see last paragraph, Chapter Two Ed.], of the Light Yoga with both the instructions on the Light of Daytime and the Light of Sleep, is given here after careful studies and contemplations. Thus one should hold it dear as most valuable instruction.