Cataloging by Form, Style, Subject Matter

[OgreBattle]

Thinking of different genres of tabletop RPG's and how to catalogue them. So there's 'genres', but what are genres describing?

A dictionary definition of genre is...
Form: What form it takes (novel, movie), material used (film camera, paper and pen, etc.)
Style: Technique involved, like different painting styles or different lighting or cut length.
Subject Matter: The stuff being shown, like an apple, a cow, economy, a certain place through time etc.

To crudely mash this into tabletop RPG's it could be...

Form: The dice or deck of cards or whatnot. Some prefer d20 some prefer a deck of cards or d6's.
Style: How those objects are used for certain results. How those cards n' dice n' stuff are used. Going with how the dice falls or DM expected to fudge.
Subject Matter: Tone of the work. Swords, Guns, Dragons, etc. The art in a book helps a lot.

Is this pretty arbitrary though? Just as a way to catalogue existing games, or maybe describe a personal heartbreaker and see "if you like X you'll like Y"

[deaddmwalking]

When you're discussing books, you usually mean 'subject matter' when you talk about genre, since books all have the same general form, and 'style' tends to be less significant than type of story. Ie, Mystery versus Fantasy/Sci-Fi. There's nothing saying you couldn't try to divide up novels by whether they're 1st-person narratives or 3rd-person narratives, but since the second is much more common and people seem to care more about subject matter than presentation style.

So I'd definitely start with 'subject matter' as your genre. Saying 'Deadlands is a fantasy Western' is probably more meaningful than saying 'Deadlands is primarily resolved with dice rolls, but some types of magic involve drawing cards'.

After using Subject Matter as a proxy for genre, talking about primary resolution mechanic is potentially helpful, but I wouldn't use 'form' as a stand-in. Saying Warhammer 40k RPG uses a d100 (roll under) resolution mechanic is clearer than saying 'the form of the RPG is d100 based'.