Jonbar Hinge

I don't think it will ever be translated to English, but there's a masterpiece of alternate history fiction written by a Korean author Bok Geo-Il, In Search of Epitaph, where a failed assassination attempt by a Korean nationalist of Japanese Prime Minister (it succeeded in real history) started a chain reaction resulting in Japan's continued occupation of Korea and Koreans losing all their identity.

Not sure why I wrote this. Maybe one day it will be translated for wider audiences - one can dream.

  For want of a nail the shoe was lost.
  For want of a shoe the horse was lost.
  For want of a horse the rider was lost.
  For want of a rider the message was lost.
  For want of a message the battle was lost.
  For want of a battle the kingdom was lost.
  And all for the want of a horseshoe nail.

https://en.wikipedia.org/wiki/For_Want_of_a_Nail

Reminds me of a short story I read recently: https://sprague-grundy.github.io/dying_to_know/

Surprised https://en.wikipedia.org/wiki/A_Sound_of_Thunder is not mentioned.

(by Ray Bradbury)

Seems like you would need time travel to know whether or not such "hinges" actually exist. The world may be so chaotically intertwined that changing anything causes timelines to wildly diverge. In fact, maybe someone could coin a term for such a measure: the ratio of historic divergence to supposed meaningfulness of a change in preceding cause-effect chain(s).

Perhaps also a measure for the opposite: the resiliency (or inevitability) of events that are "fated" to happen, albeit in different ways, despite edits to cause-effect chains. This supposes that certain events are like the centers of funnels; you can edit where and with what velocities you roll a set of marbles on its curved surface, but within a specific set of parameters they're all fated to lead to the same outcome. I can imagine a sci-fi story in which a character tries to prevent WW2 first by assassinating Hitler, then by other means, but with each edit WW2 still happens, merely with different (and unpredictable) foundational cause-effect chains. (Likely there are already stories like this somewhere.)

Interesting to consider that a Jonbar Hinge is entirely predicated on the existence of free will.