Among the Thirty-Six Stratagems, there is one known as "watching the fires burning across the river." The general idea is to stay in a safe place and watch your opponents tear each other to pieces, and only after the dust settles do you consider whether to enter the fray.
This stratagem is somewhat similar to sitting atop a mountain to watch tigers fight, but the difference is that "watching the fires burning across the river" takes place safely across the water—the strategist's primary move is to position themselves completely out of harm's way.
Sitting on a mountain to watch tigers fight is different. The observer is on the same mountain as the tigers, meaning the strategist has not withdrawn from the situation and remains caught up in the midst of it, facing the distinct danger of being targeted and taken out first by the two competing beasts.
Chapter 343