What does the arc under fingerings mean?

What does the arc under fingerings mean as seen in these two pictures? It seems like first image, the arc means to transition fingerings from thumb (left hand) to second finger, but on the second image, does it mean to transition from 3rd finger to second, and use your thumb to play the bottom note?

• Can you tell us what instrument this music is notated for?(I'm assuming piano)
– Dom
Commented Jan 5, 2015 at 14:53
• For the piano ;) Commented Jan 5, 2015 at 14:54

I think you have the order of transition wrong. So in the first image (L.H.), you'd play the high F (assuming bass clef) with your thumb (1), then the D with the index finger (2). You'd then continue holding down the D with your thumb (2), which allows you to reach down to the C (with your pinkie). So you're transitioning from finger 2 to 1 (not from 1 to 2 as you have written).

Similarly, in the second image (R.H.), you'd play the first numbered pair of notes with your thumb and index finger (1,2) then replace your index finger with your middle finger -- which allows you to use your second finger to play the G-double-sharp. My first inclination would be to just directly play the B with the middle finger, but presumably you can't do this because your middle finger is still holding down the high D. Or else I'd keep the 2 on the B, and lift the thumb to use it on the G-double-sharp. But both of these cases involve ending a note prematurely, while the indicated fingering prevents this.

For the second pair of numbered notes in the second image, you start playing with fingers four and two, then replace those with fingers five and three. This allows you to hold the notes while reaching for the low C with the thumb.

In each case, the goal of shuffling the fingers around like that is to achieve a connected legato sound, without any breaks between the notes, and without using the sustain pedal.

• Thank you for your time! Just wondering, do you use your first finger to press one note then immediately switch fingers without lifting the key (that seems hard, especially for fast pieces!) thanks! Commented Jan 5, 2015 at 17:25
• The fingering is intended to be switched without lifting the key. It seems hard to me as well, but I'm a just a poor piano player who abuses to pedal far too much. About the only finger which I can do this somewhat-reliably with is the thumb. Commented Jan 5, 2015 at 17:29
• "holding down the D with your thumb (2)" Did you mean "your thumb (1)" here?
– Lii
Commented Apr 25, 2015 at 14:05
• In this example, this is how I'll do it: 1. Press down the key with (2); 2. While holding down the key with (2), move (1) to the same key; 3. Release (2) while using (1) to keep the key in place, i.e. pressed down, without making another sound or re-striking the key. Practice slowly at first, and you'll gradually get it. Eventually you'll be able to do it at fast tempi. Commented May 11, 2021 at 6:59

On the assumption that the second example is R.H., then yes,the fingers will keep the A and C (?) down and swap to allow the thumb to play low C (?) - an arc for each change.

initial hit with the first fingering. (pre arc)

hold with the second fingering. (post arc)

so your hand can be in a better position to hit the coming set of notes.

you don't always get those fancy arcs or even fingering at all in most sheet music.