PS or SP mark, stoneware studio pottery jugs

SP or PS stoneware studio pottery small milk jugs
Well made
Mark looks very familiar but I can’t see it in the book.
Maybe I’ve had it before.
?

I've come across it before but still a mystery. Looks 70s era

More examples -

https://www.20thcenturyforum.com/t18963-tenmoku-stoneware-rimmed-vase-sp-mark

https://www.20thcenturyforum.com/t10428-little-brown-and-green-and-blue-jug-sp-mark

https://www.20thcenturyforum.com/t27696-unusual-2-handled-tenmoku-glazed-bowl-cannot-find-the-potter-sp-mark

https://www.20thcenturyforum.com/t30178-small-brown-jug-with-sp-mark

The style and quality of the pieces seems to be all over the shop.
It's hard to belive all those pots were made by the same person

Thanks Naomi.
1970s sounds about right. Lost in the mists of time.

Dan, maybe the potter was working over a few years and their pots got better. Or maybe SP stands for Something Pottery and there was more than one potter using the mark.

Tenmoku handled bowl, dish.
Same shop, pretty sure it’s the same SP mark.