Cochin China

Not to be confused with Cochin, an Indian feudatory state Cochin China, or Cochinchine, was a French colony, the southern part of what is now Vietnam.

Prior to issuing its own stamps, French colonies general issues were used. Usages can be identified by CDSs or diamond-shaped killers/obliterators with CCH. 
 * In 1886-87, printed "5" (centimes) surcharges on colonial type Alphée Dubois stamps were issued, two with an additional C. CH.
 * 30c type Alphée Dubois stamps with two "15" surcharges and a diagonal printed dividing line for cutting into bisects was prepared but never issued in 1888.
 * Imperf French colonies postage dues overprinted diagonally COCHINCHINE are bogus.
 * In 1892, Cochin China was incorporated into Indochina.

