Unified Vietnam, 5. Congress of the Communist Party (II), March 27th, 1982, Michel Nr. 1212-1213; Two stamps with nominals of 30 xu and 50 xu were issued in perforation 11.
There are some color variations on both values. Here are two different colors on the 30 xu value (light and dark, especially of the red color):
Here are the same color variations on two mint 50 xu stamps:
There is also a color error on the 50xu stamp. This pair shows a grey background and frame instead of the light blue color of the normal stamp.
These stamps were not officially released im-perforated, however a small number of im-perforated trial proofs have come to market:
Mint stamp of the 30 xu value that shows a double print of the black color. This was caused by an insufficiently tightened rubber mat causing it to vibrate during the printing process of the black color phase.
There are more also some printing errors that are more severe and hence much rarer. Below is a cancelled to order 30 xu stamp on which the entire red printing run is missing (a normal stamp is shows for comparison).
Postally used 30 xu stamp on a piece used in Dalat in June of 1982. The stamp is missing the entire red and black printing run but was apparently postally used in Dalat like a normal stamp. Also the ochre color is much lighter on the error. Very rare!
Mint block of nine stamps of the 50 xu value that shows a partial failure of the red printing run, especially on the lower right stamp. Here the red is much lighter and the harvester next to the woman with the hat is just printed in black instead of black/red.
Mint block of six 50 xu stamps that shows a significant passer-shift upwards of the red color printing run.
Registered letter sent from Nguyen Rai to Klewitz in February of 1984. It features the the Communist Party set perforated and im-perforated. Since these stamps were not officially released in the im-perforated form and represent trial proofs this is a very rare usage. The overall postage amounted to 57.8 Dong. Unusual red cancel. Green Fulda custom cachet on front.
Mixed franking of a block of four of the 50xu value together with stamps from the October Revolution and Communist Party series paying an overall postage of 2.90D sweat to East Germany in October of 1983.
Mixed franking of five of the 5xu Map stamp together with the 50xu Communist Party stamp paying an overall 75xu postage on a local letter from 1984.
Registered letter sent from Nguyen Trai to Klewitz in October of 1982. The letter carries the both Communist Party sets. The green 30 xu value of the set issued in February of 1982 shows a printing error of the turquoise color (excess color). Errors stamps on postally used cover are very rare. There is also a block of six of the 2 Dong Bulgaria stamp for an overall postage of 13.4 Dong. Green Fulda custom cachet on front.
Registered letter sent from Nguyen Trai to Klewitz in November of 1982. The letter carries both Communist Party sets and two of the rare Post Master Perforation (15) of the 12 xu Lotus stamp. The 30 xu stamp issued in March shows a double printing of the black color. Post Master Perforations and error stamps on postally used cover are very rare. The overall postage amounted to 13.84 Dong (including the rd free frank for 7.5 Dong). Green Fulda custom cachet on front.
Registered letter sent from Nguyen Trai to Klewitz in February of 1984. The letter features four of the 50 xu Bulgaria values. The two bottom stamps both show plate errors, as described above. Error stamps on postally used cover are very rare. Communist Party stamps in front and back. The overall postage amounted to 10.7 Dong. (including the red free frank of 5.5.Dong). Unusual red cancel. Fulda arrival cancel on the reverse. Green Fulda custom cachet on front.
Very rare air mail letter sent from Ho Chi Minh City to Klewitz in May of 1983. The letter carries the other half of the im-perforated Harmful Insects set plus other NVN stamps for an overall postage of 5.3 Dong. Im-perforated stamps on postally used cover are very rare. Communist Party stamp in front.
Registration Nr. 103150