should KRBN-compounds be separate from Man-RBN-compounds?
In Fusion Chess, compounds with the King are royal. So, some distinction might be appropriate. You might be thinking of a game like Sac Chess for the latter, but that game also has Amazons, which Fusion Chess doesn't have. Here are some options:
Use Pieces:Chess+Compounds more loosely
Same as above but include child tags for variations.
Make many fine distinctions in children of Pieces.
Just use names of games with certain piece sets, such as Pieces:Carrera's Chess, Pieces:Fusion Chess, Pieces:Sac Chess, etc.
A hybrid approach that uses game names for larger sets to avoid making long tags like long German words.
In Fusion Chess, compounds with the King are royal. So, some distinction might be appropriate. You might be thinking of a game like Sac Chess for the latter, but that game also has Amazons, which Fusion Chess doesn't have. Here are some options: