Seeing Form is seeing the mind, �色明心,闻声悟�,this is nondual stage.
stage 3:
Section 3.7 Use stage Answers to the Koan "Mind"
Ma Zu said, "Ordinary mind is Tao; no artificiality, right and wrong, select and discard, extinction and permanence, commoners and sages."
Hui Jue asked the King of Min, "What is the mind that Great King responds daily to thousands of differences?" King said, "Where was mind obtained from?" "Could there be a mindless one?" King said, "How is the matter on that side?" "Please ask toward that side." King said, "Chan teacher does not deceive people would do."
Chan teacher Long Ya wrote the gatha saying:
Human sentiments are dense while sentiments for Tao scarce;
How could the worldling know that Tao uses human sentiments?
Vain are only human sentiments without the use of Tao,
How much time can human sentiments last?
Tong An, in denouncing no mind, said:
Should know that the originally sensitive and unobstructed nature
May be likened to a lotus growing in the flame of a red hot stove.
Do not say that no mind is rightly Tao;
No mind is still one barricade away.
Jian says, "'No mind' belongs to the second stage. 'Red lotus in flame' belongs to the third stage. That is the so called 'one barricade away.' However, for one who has not attained no mind, red lotus in flame is out of the question. Therefore, the ancients often said, 'only when having attained to this field would do.' If one cannot die a great death in the no mind of the second stage, then merely on the basis of a bit of view points, talks about walking into a boiling cauldron; that would vainly be merely dry wisdom."
Niu Tou said:
When exactly using the mind,
Exactly no mind is using.
Devious sayings are elaborated with names and concepts;
Straight talks are free from troublesome repetitions.
No mind is exactly using,
Regular use is exactly nothing.
The 'no mind' talked about now
Is no different from having mind.
A monk asked about the original mind. Ling Duan replied, "Sit atop Vairocana; appear and disappear in the infinite space." Jian says, "The first sentence belongs to the second stage; appearing and disappearing belong to the present stage."
A monk asked about the mind of ancient Buddhas. Sheng Nian replied, "A radish from Zhen Zhou weighs thirty catties."
A monk asked, "How is Tao?" Ju Dun said, "Not different from human mind. If one realizes this, only then would one be a man of Tao. Except wearing clothing and eating meals, there is not the slightest difference from human mind, and no cheating of human mind. If one says, 'I attain, I comprehend,' then it is irrelevant."
A monk asked, "Seeing Form is seeing the mind; still see the boatman?" Cong Zhan said, "See." "Putting the boatman aside for now, what would be the mind?" Cong Zhan yet pointed to the boatman.
A monk asked about the mind of ancient Buddhas. Zhen Sui replied, "Mountains, rivers, the great earth."
A monk asked about "before any thought was born." Tou Zi said, "Truly a rude saying."