1c-15c "China Clay" Paper Varieties (331 var-340 var). Complete set of singles from 1c-15c, rich colors on paper which looks to us to be a slightly different shade than normal, 5c with top part imprint selvage, Fine, each with 1988 or 1989 P.F. certificate specifying they are "China Clay" paper, this lot is offered on its own merits due to the controversial nature of China Clay paper -- because of the White-Liston controversy, the P.F. will no longer certify these, although all experts agree the