Signed glazed stoneware ball planter

Here is a pretty stoneware ceramic with a very harmonious "ball" shape, and a pretty glaze, simple but elegant. I am leaning towards a planter but have not been able to verify this hypothesis. Indeed, I have not managed to trace the ceramist who hides under the signature (under the base, a "Phi", Greek letter), and yet he must be "known" because other ceramics with this signature give a hard time to some ceramics enthusiasts. This pot is in good general condition, no chips or chips but has a crack 4 cm from the top edge, which nevertheless remains well joined and almost invisible (see very close-up photo). It measures 14.5 cm in height for a maximum diameter of 21 cm.