In Taoist Yoga (性命法诀明指） Zhao BiChen （趙避塵） wrote about his years of finding the right teachers (or the teachers who had good or correct things to teach) and concluded that only a few he found out being worth their salts (and among them there were different levels of learning). Zhao wrote a brief biography and short commentary on each in the book's preface. Unfortunately Charles Luk chose not to translate the preface, perhaps for better organization (he actually missed out many anecdotes within the text too).
It reminded me of a contemporary master, the famous and learned master Nan HuiJin （南懷瑾). He wrote on his book on Can Tong Qi (參同契) that when he was young in China, he went to a Taoist sacred place, Green City Back Mount (青城后山) in SiChuen where lived a famous Immortal, Master Zhou who was famous for his swordsmanship. When Nan and his friend, a monk who led the way, arrived in the sacred place, it was already dark.
Nan was disappointed to find out that the Immortal had already become "spiritually immortal" (i.e. dead). He was not deterred and asked the servant there "Is there a good disciple of the Immortal that I can learn from?" The servant told him that the place had passed along to the teacher's niece (well, afterall the place was private property) who was the teacher there then. They begged to see the lady master, and she came. She questioned Nan intensively without disclosing anything about herself (which is fair, afterall Nan was a stranger to her). And she then asked Nan to show her some of his sword routine. Nan complied and the lady Master praised him. Nan told her that the highest level of Taoist meditation was what he was looking after. The lady Master remained silent but allowed them to stay for the night.
In the morning, Nan gave the lady Master some gift through her servant, and begged her servant to tell the lady Master how eager he wanted to learn, and that he was an honorable man of high morality. Nan thought if she decided not to teach, he would leave in the afternoon. The servant passed Nan's message along.
The lady master didn't come back but passed Nan a yellow paper with a diagram drawn and a mythical verse written， plus a verbal message "I'll see you tomorrow morning". The diagram was a double circle with a dot at the center. The mythical verse is as follows:
Those who know the great Way to Green Mount
Secretly and openly the teachings be found
Nan immediately left the place. The diagram, according to Nan, was simply "meditation at one's Dantian" (very preliminary stuff, and the lady master played it up so high!). Besides, again according to Nan, the lady Master was at her 40s, with fat belly and eyes lacking in fire. Nan didn't think she was much into Taoist meditation herself!
Contemporary seekers of Taoist meditation are more lucky. Now one can read books, take a course (or many courses), search the internet etc. But then one important requirement remains the same in all history: the ability to spot a good teacher. A prerequisite is that one must practice diligently together with a smart and inquisitive mind!
That actually reminds me of one article that I read from the internet. It gave me a good laugh then. There it wrote (I'm paraphrasing), "Look at the big belly of my good teacher (actually a diseased famous teacher in USA with many books to his credit). Those are not fat, but are chi, loads of chi!"
What can I say?