I had this idea about having a rule for certain duals in my world being use your opponent’s weapon/skill (with agreed time for practise). A recent post you had was talking about how no one can be experts at everything, which means unless all are impossible experts like that, one may be severely disadvantageous or both look like sloppy amateurs who can’t fully use the weapon/skill especially if it’s very different. So.. is my idea good or not?
No, not as stated. Let’s talk about why, because there is something adjacent that, the best of my recollection, was a practice.
In real history (and in your world) dueling was a highly ritualized activity. There was an entire process that was necessary to “legitimize,” a duel. The exact steps varied through history and between cultures. The goal was to provide a form of dispute resolution, but the rituals evolved to minimize the risk of bloodshed without taking the option entirely off the table. If the process was skipped, then you just had two people trying to murder each other.
Generally speaking, you do not want someone planning to kill you handling your weapon. There are far too many ways to covertly sabotage it when you have it in hand, and are appearing to, “practice.” If you’re not above poison, you could even booby trap your foe’s weapon if given the opportunity.
There’s a few things about dueling worth discussing.
First are the seconds. The second was a personal friend who served a critical role in dueling process. I’m unsure exactly when the process started, though it was well established by the 19th century.
Seconds had a number of responsibilities, including: Coordinating the duel’s schedule (usually the duelist who accepted the challenge could dictate this, within reason, and it fell to the seconds to lock down the details.) Making any necessary preparations. Procuring, inspecting, and providing the weapons. (Depending on the culture, this might include examining In the case of pistol duels, the seconds were responsible for loading their duelist’s weapon. Finally, they were tasked with talking their friends out of killing each other.
Dueling sometimes had very specific rules regarding the kind of weapons used. This changes based on when and where you are. In some cases, the duelists would have some freedom, (as with the location, if there was a choice, the responding duelist would usually be allowed to make this decision, within reason.)
The important takeaway is, while one of your duelists may have a significant skill advantage, their weapons should be evenly matched, if not outright identical. There’d be no benefit to, “practicing,” with your foe’s weapon, because you already, effectively, have a copy.
All of this is distinct from, “dueling,” in narrative. This has nothing to do with dueling rituals; dueling in fiction refers to a specific, small scale (usually one on one), combat cadence. The fight occurs with alternating flurries of violence, interspersed with quiet lulls. In some cases, those lulls will include dialog, where the characters verbally spar, though in others, it will feature downtime while the characters reposition, or while the focus cuts away to other characters. This structure works very well on film, and is extremely popular in screenwriting.
Because of their structure, duels can extend far beyond a single scene. While you can have a simple single fight duel, like Obi-Wan and Vader in A New Hope, you can also drag this out over an extended period of time, moving between different environments, such as Luke’s duel with Vader in The Empire Strikes Back.
Narrative duels can also extend beyond a single character. Many nautical novels include dueling ships. Each ship is (functionally) a single participant in the overall combat. Science Fiction often takes inspiration from nautical sources, alternately patterning starship combat off of sea combat, submarines, or, sometimes, modern aircraft support. For example of this, the majority of Wrath of Khan can be described as a protracted duel between the Enterprise and the Reliant (or between Kirk and Khan as the respective captains), while drawing heavy influence from both submarine combat and the Horatio Hornblower novels.
The identifying characteristic to identify a duel like this is if the combatants remain under threat of immediate violence from one another, even when they’re moving through different spaces. I realize this is a little subjective. If you want a more definitive set of thresholds, if either character is defeated or fully escapes, the duel is over.
If you’re working within the narrative structure, it’s entirely possible that one character will end up with the other’s weapon via some means. They may have simply disarmed their foe and are now pursuing with both weapons in hand. As far as tension goes, this is a good idea, as it forces your character to find a replacement under pressure.