A report from 15 years ago. The battered cover, reduced on bottom, is addressed to the Italian Consul at Yokohama, in syllabics ka-ru-?ya (not probably a “Carlo…”). Sender is the Japanese consulate at Pusan/Korea.
Stamps franked are Japan “Old Koban” issue 1876 5 sen brown (x5, including a part bottom-margin imprint copy) and 2 sen violet of 1879 (x2) making a hefty 29 sen. Another stamp right to the torn/halvened one has fallen off. Probably another 5 sen stamp, which would make a total of 34 sen: should consist of 6 sen registration and 28 sen for the letter (14-times weight).
The japanese double circle datestamp type DK has 釜山浦 (Fusanpo*) in the inner ring, the outer ring shows “朝鮮 [Korea] -.5.19” or May 19. On reverse we have a delivery marking, double circle type dN3B2 of Yokohama 横浜 dated “15.(5.)30 2nd” or May 30, 1882.
The frontside shows a boxed vermilion vertical marking 川支延着 “delayed arrival by river [sc. flooding]” which was applied upon arrival in Yokohama. The cover travelled by Japanese steamer from Busan to Nagasaki and then onward by steamer/railroad.
Source: this cover was offered on Ebay in April 2003. Cover whereabouts currently (August 2018) unknown. Italian seller-ette stopped sale despite several actual bids and pretended “can not find cover anymore”. A guess is it went to a well known “philatelic-broker-black hole” in Hokkaido, Japan. A certain Dr. X was known in the scene for such actions (against Ebay regulations) to finance his gambling addiction. He is no more with us. To the best of my knowledge, the cover did not surface again…
*釜山浦 / Fusanpo was the gated port/customs settlement area for officials/foreigners as opposed to the Korean old town of 釜山鎭 / Fusanchin. The latter was several miles northeast of the port district up the mountains.