joseki; standard sequence of moves
Go term: a well-studied, locally optimal sequence of moves, especially in a corner.
This joseki is often used even in professional games.
standard practice; established tactic; formula
Figurative extension from Go: a conventional, reliable way of handling a situation.
There is a standard approach to solving this problem.
He proceeded with the negotiation by the book.
雪崩 (as ナダレ) names a specific famous Go corner pattern, while 定石 is the general term for any established Go sequence.
From 定 (fixed, established) + 石 (stone), originally referring to a fixed sequence of stone placements in the game of Go.