O15 (O20b) 1898 5d purple-brown Otira Gorge, unwmkd, perf 11, greenish blue "O.P.S.O." handstamp, extremely rare as it is one of only two stamps in the whole issue so overprinted, listed but unpriced in Stanley Gibbons, well centered, light "Wellington" cds, ex-Pattiz.
