What is a good justifying reason and timing for a flashback? I noticed today that without a justifying reason and good timing that a flashback is just terrible. For example, in my story there's a soldier who's having a flashback in the middle of a fight and is thinking about the meal he had 2 years ago. Usually, a flashback is at the beginning of a chapter or something like that, and from what I recall it is also good to do it for exposition or explaining a character's background to show the readers why the character is evil or behave in a particular way, but I doubt this is exhaustive. Is there a general reason or better reason for doing a flashback and how do we time them correctly?
The secret, to any device, is to make the reader desire it so that when you deliver it they gobble it up. If enough curiosity is stoked in the reader, first, about that thing that happened way-back-when, then the reader will love the entire chapter of back story.
Imagine the flashback scene of Severus Snape, James and Lily Potter, and some of the other characters, when those characters were students. We learn that Severus was falling hard for Lily and some of the other students bullied him.
Enough intrigue had been built up around the history of those relationships, previously, unfulfilled knowledge, that the audience was salivating for details.
And so, if you are determined to use a flashback instead of gradual reveal through context and recollection, make the audience want the flashback before you deliver it.
My rule of thumb is: only do flashbacks--or give background information in any form, period--when it's relevant to the story.
Start close to the action and stay with it, and only give background information if something is happening in the story that makes the reader think some kind of question like: geez, huh, how was he able to do that? Or why do they hate robots? etc.
A little backstory goes a long way. Read Anton Chekhov’s short story, The Bet. He starts off with a smidgen of backstory and that’s it!
Or the first chapter of Carson McCullers’s Heart Is A Lonely Hunter. She places background about the protagonist, Singer, past the denouement. The entire amount of backstory in the book is 14 sentences in two compact paragraphs. Here’s how it starts:
“There was one particular fact that he remembered, but it was not at all important to him. Singer recalled that, although he had been deaf since he was an infant, he had not always been a real mute. He was left an orphan very young and placed in an institution for the deaf. He had learned to talk with his hands and to read… (next paragraph) At the school he was thought very intelligent.”
This backstory increases the tension because now we know that Singer has no other family, and she also adds that he’s smart, and he had only known Antonspoulos, the other deaf mute, since moving to the town. McCullers doesn’t even say why he moved there.
McCullers starts off the scant backstory with the words “…,but it was not at all important to him.” It is as if she knows backstory will help the reader, but she resists it, too.