1891-97 Watermark Crown over NSW 1d Green Perf 10 horizontal pair error 'Imperforate Between and at Left', showing portion of adjoining unit at left, very fine and cancelled Kurrajong cds, JY 9 1891. The only recorded piece, and the most important item of New South Wales postage dues and a major world postage due rarity. BW ND2b cat AU$12,500, SG D2a cat £6000