1992, $1.80 Chinese Opera, gray omitted (Scott 658 var. 2016 Yang C379a), the error the bottom left stamp in bottom left block of four with plate numbers and color blocks; top stamps with gray (inscription and denomination) at bottom, the bottom right stamp lacking inscription but bearing the gray "1A" plate number at bottom, Post Office fresh and sound, o.g., never hinged, Very Fine, an attractive positional. 2016 Yang HK$5,000+.