We use the Stamp Catalogue of China 2010 (also known as the "Chan Catalogue") as a reference, as it is the most complete and accurate reference book on Chinese Philately. The item "CHINA- SHANGHAI- BLOCK OF 20- 15cts- POSTAGE DUE- COMPLETE- MINT- NH- RR" is in sale since Thursday, May 4, 2017. This item is in the category "Stamps\Asia\China". The seller is "jmcoins2009" and is located in Presinge. This item can be shipped worldwide.