I've commonly seen a plot hole defined as an inconsistency or contradiction in a story that can't be explained, which I don't agree with because fans can explain absolutely anything if they put their mind to it. I plan to do it for every plot hole I encounter even while acknowledging it as one. I'd say that if the fan has to come up with their own explanation, rather than the story providing it, there's a good chance that you've got a plot hole on your hands.
A plot hole can then be defined as a missing plot point that is needed to reconcile two previous plot points. Plot point C can't be reached from blot point A without plot point B, but plot point B is never provided by the story and a plot hole is created.
There'd be some cases where a the story doesn't provide the answer to a question that I wouldn't consider a plot hole because the story doesn't demand that the question to be answered to be able to continue - a good example of this would be Ginyu's loyalty to Freeza. It's an often asked question why Ginyu works for Freeza instead of stealing his body with his body changing ability, and the story certainly never answers this directly. But I don't think it's a plot hole because the story also doesn't give readers a concrete reason to assume that Ginyu would want to use his technique on Freeza.
Ultimately determining whether a suspected plot hole truly is one or not is going to involve some amount of subjectivity, so I don't expect everyone to agree with the conclusions I come to when I look at potential plot holes. The most important thing to me when I'm doing so is to be consistent with how I evaluate them and what conclusions I draw.
Aside from plot holes I'll also be talking about contradictions, inconsistencies and retcons. These three aren't necessarily the same as plot holes, and will usually be much clearer to identify and require a lot less subjective thought than determining plot holes. The only thing I feel I need to explain about them is what a retcon is.
Short for retroactive continuity, a retcon is exactly that: continuity introduced retroactively into the series. However, there seems to be a significant numbers of people who believe that retcons are inherently contradictory, which doesn't have to be the case. A retcon can be introduced to a story without creating any problems with previous continuity, so calling a plot point a retcon doesn't always mean that a contradiction, inconsistency or plot hole has been created in the story because of it. Conversely, a plot point isn't automatically not a retcon because it doesn't create inconsistencies in the story. That's important to keep in mind for when I discuss any of Dragon Ball's retcons - calling something a retcon is not a criticism!
I felt it was necessary to bring these points up separately from the reading itself, to better set up how I plan on analysing these issues and to avoid spending too much time on it when I come to the first potential plot hole I wish to look at - especially since that happens as early as page 13 of chapter 1!
