How applicable is this

[ongaku_oniko]

Okay, I mean I know this is a very general question, with different answers for different people, but just generally, I was wondering has anyone ever come across this

https://www.pianofundamentals.com/

?

If so, how applicable are the advice in there? I see some things that follow mainstream teaching, but some that seem a bit less ... mainstream. And there's not enough explanation on how to do certain things, like "relax" your fingers. It's a HUGE read for people who haven't seen it before, so don't bother unless you wanna learn how to play the piano. But if there are some knowledgable people who have seen it before, what do you think of that site?

[stevebob]

There have been innumerable past discussions about the book and the author's ideas.  If you use the Search function for the terms Chang and/or "Fundamentals of Piano Practice", you should find what you're looking for.

In a nutshell, the book is poorly written and probably not worth slogging through in its entirety.  Many people have found some useful information, sound principles or novel suggestions, though, while disregarding what was found unhelpful, uninteresting or bizarre.  (That was my own experience, too, for what it's worth.)