piano chord
Gm7
G1B♭♭3D5F♭7
Minor triad with a minor seventh. The same four notes as a major sixth chord a third above.
What is true of it
Gm7 is G, B♭, D and F — 1, b3, 5 and b7 counted from G.
These are also the notes of B♭6/G and A♯6/G. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.