Pianophilia

I'm wondering if anyone knows the meaning of the pedal markings in this excerpt from S. Maykapar's Bagatelles (Biryulki, Op.28).
The scores of nearly all the pieces are sprinkled with the normal "Ped" marks but there are also a very good number of the same "Ped" preceded by a small open circle: "o Ped"

I have no idea what these "o Ped" marks mean. I thought at one point perhaps they are a "soft" pedal mark, but no- I found some being used in a fortissimo section. Perhaps they are an indication of rhythmic pedalling - whereby the pedal is depressed at the same time the note is played?

I checked one of the original manuscripts and yes, Maykapar indicates "o Ped" in his own hand.
Anyone have any knowledge of this mark, what it means, or have an opinion or guess?

Here is a screenshot of the score of one of the pieces:


Thanks,
Steve Szyszkoski

Well, the example I included was not the best because one could interpret the markings as pedal changes.

But in many other places in the scores of these pieces the "o Ped" marks are given with a "clean" start, i.e., when all the dampers are seated.

These markings occur quite frequently in Maykapar's music, notably in his ""20 Preludes for Pedal" op 38. There is a full explanation of them in the Prhythm edition of op 38, sadly out of print and as far as I know unobtainable anywhere.

As far as I can recall, they mean that you should depress the sustaining pedal half way, or thereabouts, in order to introduce a kind of harmonic "stop" to the piano strings. You can also find these circle signs in notation for string instruments where harmonics are produced.

Unfortunately it doesn't work on most pianos because all the dampers are different distances from the strings!

Thank you!