1906 10c grass-green, perforated 11, serial no. 937, unsevered strip of four (folded between stamps in the middle), Dragon's head facing downward, unused, v.f., extremely rare (Chan E2, cat. $12,000). Complete unused strips of four are exceptionally scarce because the first section (#1) was to remain in the Post Office receipt book, (*) Catalog #E1 Catalog Value $ 12,000