Part of French Indo-China ( Protectorates of Annam, Tonkin, Cambodia, Laos, and the colony of Cochin-China), Annam & Tonkin has six stamps recognized by Scott with major numbers. Actually, only three stamps (those illustrated), and another set with a hyphen between the "A" and "T".
These stamps were issued in 1888, and handstamped surcharged "A&T" with the value on 1881-86 French colonies stamps. The protectorate had a population of 14 million in 1890.
100 Centimes = 1 Franc
1888 Scott 1 1c on 2c brown/buff overprint with "A & T"Big Blue Picture
The least expensive stamp is valued at $35, which might explain why the protectorate never appeared in Big Blue.
Big Blue Checklist
1886 Map of Indo-China: Note Annam & Tonkin located in present day Northern VietnamKinds of Blue
1888 Scott 2 1c on 4c claret/lavander overprint "A & T"Big Blue Bottom Line
As Scott's Big Blue is the most popular "serious" international album in the U.S., nice to know when a stamp issuing entity is NOT there. :-)
Note: Map appears to be in the public domain.