The reason I am not seeing 久 as the symbol is because the second stroke is a single stroke like in フ. In the painting, the symbol uses 4 strokes. Like ケ with an additional stroke. 欠 just seems to make sense in this context.
I agree with your reasoning. It doesn't seem exactly like either in the painting, although 欠 certainly fits better. My guess is if you're not correct, you are certainly on the right track.
The reason I am not seeing 久 as the symbol is because the second stroke is a single stroke like in フ. In the painting, the symbol uses 4 strokes. Like ケ with an additional stroke. 欠 just seems to make sense in this context.
I agree with your reasoning. It doesn't seem exactly like either in the painting, although 欠 certainly fits better. My guess is if you're not correct, you are certainly on the right track.