Vase incised WAL mark, ‘77 date, Any ideas??

I have this very large and heavy Vase.
Any ideas greatly appreciated.

It looks quite an interesting piece. But the lettering of the signature looks somewhat crude for a professional potter. The lettering is all straight lines. A professional signature would be more fluid and natural as it would have been used a lot.
Equally heavy is not necessarily a good sign. A professional potter would make it as light as he could, as it saves money and actual physical energy. Working with wet clay is hard work!
Yet it is a nice shape. I would think it was by a very good hobby potter.

Thank you Philpot for your input.