What was the rate for mail to Korea?

During the second half of the 19th century, the foreign powers sought to increase their influence on Korea. Christianity was spreading slowly and covertly by underground French Roman Catholic missionaries. The Korean government outlawed Christianity and sought to curb foreign contact. The Korean repulsed military interventions by France (1866) and the US (1871), which attempting to establish trade relations. In 1876 Japanese forced Korea to establish diplomatic relations in order to begin trade, thus weakening Korea’s traditional ties with China. China then sought to neutralize Japanese influence by promoting Korean ties with Western countries, beginning with the 1882 Korea - US Treaty that agreed to open Jenchuan, Yuensan, and Fusan for trade. Mollendorff (Paul Georg von, 1848-1901, a German officer in Chinese Customs) was recommended by Lee Hung Chang (1823-1901, Governor of Chili and Minister of Trade for Northern Coastal Provinces) to take the position as diplomatic advisor to the King of Korea and Chief Officer of Customs. The Customs office had been selling Chinese postage stamps and handled customs and public mail matters. The Customs’ mail service was ended on Jan. 1, 1900 when Korea joined the UPU (also according to Mizuhara's Postal History of Korea, the Chinese Customs in Korea operated postal service from 1889 to the end of 1898). Finally, the (Chinese) Customs itself stopped operation in Korea after Japan’s victory in Russo-Japanese War (1904) and the Treaty of Portsmouth of Sep. 5, 1905.

The earliest record for postage rate to Korea I found is from The History of Chinese Postage Stamps vol. I, page 318: Customs postage Rate Table. The letter rate in 1883 for Korea was 6 ca. (per ½ oz.), the same rate as that for US, Japan and Hong Kong. The rate was repeated in 1892-1893 Table, and the last one is from Customs Courier Service: Winter 1894-95, the rate was still the same 6 ca. However, I could not find any example of mail for Korea from the entire Customs Post period so far.

Stamp Catalogue of China (1897-1949) edited by Shiu-Hon Chan, page 422, Postage Table listed Korea in the same rate category with Japan, Formosa (Taiwan), etc. The rate was listed as 10 cents (per ½ oz) from the start of Imperial Post on Feb. 2, 1897. From existing covers and Postal Secretary’s Circulars No. 13, I think this is incorrect.

From existing covers we know that letters dispatched from Customs in Korea to China were charged domestic rate, which was 3 ca. (9 ca. for oversea destinations via Shanghai) or 4 cents. I think it should have been the same rate for mail from China to Korea. Unfortunately existing covers to Korea are so rare that the only two covers* I could find are from The Red Revenue Surcharges - China 1897 vol. II, which bearing 4c and 8c postage respectively, both dated July 16, 1897 from Shanghai to Chemulpoo. By the way all of these 4 covers were sent to the same addressee "E. Meyer Co." The Chinese name of the company was 世昌, it had setups in Tientsin, Shanghai and Hong Kong as well. Speak of mail matters from China to Korea during that period, official mails were carried by ships of the Chinese Navy 北洋水師 (Pei-yang - Northern Fleet), commercial mails were usually sent to foreign offices (in Shanghai) for transmission. Therefore, mail to Korea through Chinese Post was rare, and survived covers were like black swans.

On October 19, 1898, Postal Secretary’s Circulars No. 13 was issued from Peking by Acting Postal Secretary Aalst (Jules A. van, 1858-?, a Belgian officer in Chinese Customs and Post):

The Inspector General instructs me to state as follows:--

1.-- The experimental tariff and rules published in Notification No. 20 will cease to be in force after the end of December next and will be replaced on 1st January 1899 by the tariff and rules hereto appended.
... ...
3.-- As regards letters, it will be seen that a limit of weight and size has been fixed for each single cover; that letter for Formosa and Korea, and also for Lungechow, Mengtsz, and Szemao, must pay postage, not at the domestic rate as heretofore, but at the rate set forth for Union countries; that postage is compulsory for domestic places and non-Union countries, ... ...

From this document we know that:
The postage rate for Korea was the same as domestic rate prier to Jan. 1, 1899.
The rate for Korea changed to international rate (for Union countries) from Jan. 1, 1899.
However, what we don’t know is exactly from when (sometime in 1895 - 1897) the domestic rate was adopted for Korea. I hope that whoever visited my site could provide any information regarding this mystery.

* Additional Information by Editing Team Leader of the POSTAL HISTORY SOCIETY OF CHINA:

In Meiso Mizuhara’s 1998 edition of Korean Postal History 1884-1905 page 349, he called our attention to the absence of covers from China to Korea, where he wrote:
(5) Mystery of Arrived Cover
In addition, a great question related to the matter has been raised: No cover transmitted from China to Seoul or Incheon by the Customs Post in Korea has been found. In general, a postal service handles mails back-and-forth. Therefore, it is quite odd that there is no example of mail sent from China to Korea, where there are covers of Customs Post in Korea sent to China from Seoul or Incheon. Except for the unique cover sent to Pusan by Customs Post, which the present writer is going to mention later, why there are no such examples? It is, therefore, critically important to find some data to solve the question.

(There) is a Chefoo Customs Mail Matter cover in Sam Chiu’s exhibit, Chefoo 1880 to 1911. On the back of the cover are 2 strikes of the Chefoo Dollar Chop in brown of 1897 MAY 7 from the originating post office. There were no receiver on arrival in Korea. … … Paul has already mentioned that there were only 2 other covers recorded addressed to Korea in this period. This is only the fourth together with Mizuhara’s Pusan cover. This is here … … to complete the record on the rarity of covers sent from China to Korea (in the Customs Post and early Imperial PO period).