[Jap2-0]

B♭ isn't the relative minor of C♯? I think that'd be A♯ minor.

Edit: Actually B♭ minor is the enharmonic equivalent of A♯ minor. IE another case of things in music that are the same but aren't.

[ska]

I thought of adding the comment about enharmonics but it decided it would muddy the water further and edited it out. Should have left it in.

[jcpst]

Enharmonic in the context of 12-tone equal temperament!

slowly backs away

[Jap2-0]

Oh no you don't

And now I'm down the rabbit hole of reading about tuning systems again.