Translation by Ryuei:
Translation from here (PDF):Hsiu-hsiu-an Discourse on Sitting Meditation
Generally, to practice sitting meditation one must reach the highest excellence and ought to be naturally alert.
Cutting off thinking and yet not falling into dullness is called “sitting.” Remaining without passion in a passionate situation and without defilement when dwelling amidst defilement is called “meditation.”
Allowing nothing external to enter and nothing internal to leave is called “sitting.” Having no abode and depending on nothing while constantly lighting the way before one is called “meditation.”
Remaining unmoved when the outside world is moving and staying quiet and free from agitation in the middle of it all is called “sitting.” Turning the light back within to illuminate and discern the root source of all phenomena is called “meditation.”
Refraining from acting on the favorable and unfavorable circumstances one is faced with and likewise not being turned aside by the distractions of forms and sounds is called “sitting.” Illuminating the darkness so that the brightness exceeds that of the sun and moon and transforming matters so that virtue overcomes heaven and earth is called “meditation.”
Entering the samadhi free of distinctions when surrounded by distinctions is called “sitting.” Displaying the wisdom which discerns distinctions even when there are no distinctions is called “meditation.”
In summary, the blazing work of the function in accord with the correct substance of the absolute is called “sitting”; while attaining the sublime throughout one’s length and breadth and thereby finding no obstructions when dealing with any matter is called “meditation.” These words are just a summary because no amount of paper or ink can thoroughly exhaust [the real meaning of sitting meditation].
The Naga’s great samadhi is neither quiet nor moved. It is the true thusness of the wondrous substance, which has no appearance and no disappearance. It cannot be seen when looked upon nor heard when listened to. It is empty yet not empty; being yet not being. It is vast enough to encompass what has no boundaries yet so minute that it can enter what has no inside. It is the universal spirit of knowledge and wisdom, radiant light, longevity, the great moving power, the great function, unexcelled and inexhaustible.
Someone with an aspiration [to be enlightened] should examine this fully in order to act in accord with the great enlightenment. After the single voiced roar [of awakening] the multitudes of subtle powers will all be complete in oneself. How can this be compared with the powers of darkness outside the Way transmitted by those claiming to be teachers who take what they have gained to be the final goal?
Hsiu-Hsiu Am Discourse on Za-Zen
Generally, to practice Za(sitting)-Zen(meditation) is to reach the mental state of highest excellence and to be in the state of complete alertness.
When the mind is devoid of any thought and yet no drowsiness takes place, it is called Za; if there is no passion in a condition which fans it and if one transcends defilements in which one is, it is called zen.
When neither external sense-object enters the mind, nor the mind goes out towards external things, it is called Za. If the mind is neither attached to anything nor depends on anything so that the constant light illuminates, it is called Zen.
If the mind is not moved when the external conditions shake it and if the mind is quiet and free from agitation, it is called Zen. If the light going out is turned inward so that the source of the self-nature is reflected, it is called Zen.
If the mind is not agitated either by favorable or adverse conditions, nor is it rolled over by color or sound, it is called Za; if the light surpasses the sun and the moon when it illuminates the dark area, and if virtue surpasses heaven and earth when transforming things, it is called Zen.
To enter the state of samadahi in a condition of discrimination is called Za; to have the discerning Prajna in the condition of no discrimination is called Zen.
In conclusion: to keep the true nature of samadhi serene while the mind works like a blazing fire is called Za; to attain boundless wisdom and thereby to do things without any obstruction is called Zen.
Za-zen can be summarized briefly as this. However no amount of ink and paper would be sufficient for a detailed illustration.
The great Samdahi of Naga is neither quiet nor moved; the wondrous nature of True Thusness is neither born nor annihilated. Neither can it be seen when looked at, nor can it be heard when listened to. It is empty and yet it is not; it exists and yet it does not. It is as vast as to envelop what has no boundary and it is as minute as to enter what has no inside. The magic power, light, longevity, great moving power and the application of the one who is enlightened to it are inexhaustible and limitless.
If one with an aspiration to be enlightened practices Za-Zen in a proper way until one attains the great enlightenment, one will be filled with various powers of wondrous spirit at the roar of awakening. How could this be compared with the wicked heretics who, with their instructions, claim to be teachers, and who take what they gain to be the final goal?