RARE! Vernon Kilns Pottery Coral Reef blue 'test' plate 9 & 3/8" Don Blanding design buying Unusual mark(s) EX!!! 1940

Up for sale is a rare Vernon Kilns Pottery blue Coral Reef test plate measuring 9 & 3/8" across. This test plate, with design by Don Blanding, features two unusual marks; a round VK ink stamp in a configuration that I've never seen before and a hand incised #1. Also, the blue decoration is in a much darker blue than production Coral buying Reef dinnerware and in some places appears to be two shades of blue. The Coral Reef pattern was only made in 1940. This plate is in excellent condition with no chips, cracks, crazing, or repairs. It is also totally free from utensil marks or scratches.