Xuansha

A monk said, “I’ve just arrived here and I beg the master to point out a gate whereby I may enter.”

Xuansha said, “Do you hear the sound of the water in Yan Creek?” The monk said, “I hear it.”

Xuansha said, “That’s the place of your entry.”

Joshu

A monk asked, “What is the substance of the true person?”
The master said, “Spring, summer, autumn, winter.”
The monk said, “In that case it is hard for me to understand,”
The master said, “You asked about the substance of the true person, didn’t you?” (The Recorded Sayings of Zen Master Joshu)

Ah, the delicate interplay of relative and absolute again…

Shishuang

'A monk asked, “What is the intention of coming from the west?” 
The master said, “A single stone in space.”
The monk bowed. The master said, “Do you understand?”
He said, “I don’t understand.”
The master said, “I trust you don’t understand. If you understood, I’d bust your head.”' (Jingde Chuandeng Lu)

Or, the note says, the stone would bust the monk’s head. Either way, this one got lucky.

Fayan

A monk asked, "What is the thing toward which an advanced student should pay particular attention?"
Fayan said, "If the student has anything whatsoever which is particular then he can't be called advanced."

Ouch.

Caoshan

'Yunmen asked, "The unchanging person has come. Will the master receive him or not?"
Caoshan said, "On Mount Cao there's no spare time for that."'

So many wrong turnings here.

Yantou

Ruiyan asked Yantou, “What is the fundamental constant principle?”
Yantou said, “Moving.”
Ruiyan said, “When moving, what then?”
Yantou said, “You don’t see the fundamental constant principle.”
Ruiyan stood there thinking.
Yantou said, “If you agree, you are not yet free of sense and matter; if you don’t agree, you’ll be forever sunk in birth or death.” (The Book of Serenity)

If I had been Ruiyan, I would not have stood there thinking.

Fen-yang

‘A monk asked Fen-yang, “If there is no bit of cloud in the sky for ten thousand miles, what do you say about it?” “I would punish the sky with my stick, ” Fen-yang replied. “Why do you blame the sky?” the monk persisted. “Because,” answered Fen-yang “there is no rain when we should have it and there is no fair weather when we should have it. ”’ (The Iron Flute)

Nyogen Senzaki’s commentary: A Zen monk punishes everything with his big stick; even Buddha and the patriarchs cannot escape that blow of Zen. His stick is the handle by which he can shake the whole universe. If there were to arise any disturbance in the perfect network of the universe, Fen-yang was ready to set things right with his stick. The monk was merely a dreamer expecting to live in uninterrupted bliss while he worshipped a white-washed, dummy Buddha. Fen-yang’s first answer was really a warning to the monk, but when he saw the monk did not understand, he simplified his answer as one might to a small child. 

My commentary: Perhaps we can think of this as a koan for California.

Shishuan

‘Shishuan entered the hall and addressed the monks saying, “All of the buddhas and all of the buddhas’ anuttara-samyaksambodhi come forth from this sutra.” He then raised his staff upright and said, “This is the Nanyuan Temple staff. Where is the sutra?”

After a long pause he said, “The text is long. I’ll give it to you later.”

Then, with a shout, he got down from the seat.’ (Zen’s Chinese Heritage)

Kids these days, no attention span, eh?

Shitou

Daowu visited the assembly of Shitou and asked, “What is the fundamental meaning of buddha dharma?” 
Shitou said, “Not to attain, not to know.” 
Daowu said, “Is there a further turning point in going beyond?” 
Shitou said, “The vast sky does not keep white clouds from flying.” 

Daowu auditioned for the role of a white cloud, but couldn't nail it.

Xuefeng

'Xuefeng asked a monk, "Where are you going?"
The monk said, "I'm going to do community work."
Xuefeng said, "Go."

Yunmen said, "Xuefeng understands people according to their words."
Hongzhi said [about this dialogue], "Don't move. If you move I'll give you thirty blows. Why is this so? For a luminous jewel without flaw, if you carve a pattern its virtue is lost."'

This is a classic example of a koan illustrating non-abiding. Both answers are perfect, but you cannot stick to either.