What is a Robert Hart cover?
Probably for security reason and ease of recognition, Hart had ordered his covers and letter papers printed with a raise grain logo with his initials "R H" in red ink printed on the back flap of his covers and at top center of his letter papers. The printer is the well-known UK stamp printer, Waterlow & Sons, as their name is also embossed along the inside edge of the covers. To Chinese collectors, Waterlow is famous for printing CIP's first issue, sometimes referred to as the Waterlow Dragons. With his "logo" on a cover or letter paper, you don't need to get a certificate to know that it is a genuine Robert Hart cover. Furthermore, Hart's handwriting is very distinct and is full of character.

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What is the "big deal" with a Robert Hart cover and how come there are so few?
As Hart is the "father of the modern Chinese Post Office" and can also be called "the father of Chinese stamps", besides his other achievements in the Chinese Customs Office, his contribution to China's postal system is unparalleled. Can you name another person who can compare with Hart's achievements and influence to China as a nation? Since the publishing of the Hart-Campbell correspondence, we know that many of his letters, to Campbell or others, made references to many of the, then, current and important affairs of China. These letters were also written from someone who had a most privileged vantage point. We have not seen another correspondence that is as important as this and from an insider's point of view.

I believe that there is no one single reason why so few Hart covers have survived. However, we know that Hart sometimes "enclosed as much as 10 letters" in his letter-package to Campbell. Campbell would then send these out individually from London. So Hart may have send small parcels rather than single letters. And we know no one keeps parcel wrappings. Furthermore, as a Customs official, from 1883 onwards to the end of 1897, no Chinese stamps would be used on Hart's letters, but only the Customs Mail Matter marking, and nearly all would have been Peking's I.G. Mail Matter marking, franked with foreign (or offices in China) stamps. It is only from January 1898 onwards where Hart covers may have been franked with stamps and collectors may have "accidentally" kept these covers, as these have "stamps" on it. We see that our earliest recorded Hart cover has a date of September 1898, which is consistent with this observation.

I believe that there is actually many times the number of Hart cover in existence than the 13 that we recorded. Many have not been identified as such, due to the current owner's lack of this knowledge, and therefore are not reported.
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---- Extracted from Sam Chiu's article, Robert Hart Cover, Postal History Society of China Journal Vol.1, No.1, page 9.