I've been trying to determine if there is a rule for when indefinite pronouns
(何か, だれでも、 etc.) require a particle.

It _seems_ like if the required particle is を or が, it gets "absorbed" into
the pronoun...but not always?

Perhaps the particle is acceptable, but optional and usually omitted?
CC BY-SA 4.0
2018-11-24T21:48:36.897
63026
2018-11-24T21:48:36.897
21736
question
grammar
How do I determine if an indefinite pronoun requires a particle?