I'm learning piano and came across an exercise called broken chords, when you play arpeggios for every inversion of a particular 7th chord.
The problem is that different sources use two types of fingerings.
Let's say we are playing a root position of Cm7 in the left hand.
some sources like ABRSM guides strictly follow the rule "no thumb on a black key". So the fingering is 5312.
other sources ignore that rule and use thumb very often. The fingering is 5321. In this sources position of the hand always looks like we are ready to play blocked chord.
Is there reason for this difference? What fingering would you recommend?