The exact date when the second series was issued is not featured in the catalogues. All they state is 1945/1946. The second series is philatelically more interesting as there are some rare perforation varieties, some of which have not even be catalogued yet. Take for example the 3c value of the set below. It is catalogued by Michel with three perforation varieties (14:14, 11.5-12:14 and 11.5:11.5) however this stamp is perforated 12:12 so is as of yet unlisted. There are also different kind of colors on the original stamps (please see the 30c and 40c values below), Finally, on the 15c value there are two different kind of colors for the overprint (again, see below). One in the standard black and one in dark green. There are a number of known errors on the series that either stem from errors on the original stamps or errors in overprint.
Below is the 3c value with a partially missing overprint (the country name “Vietnam” is only visible in a fragment):
The 30c value in orange-brown is also known with a double overprint:
Here a rare multiple in a mint bloc of four in the very rare Perforation 11.75 (unlisted in catalogue):
Extremely rare imperforated 15C stamp with the green overprint from the top margin:
As described under the first series of the overprints postally used letters are very rare. Below is a local letter with an interesting mixed franking of the dark-green and black overprints on the 15c value. It is correctly franked with 30c but probably has a philatelic origin. Nevertheless, a very rare mixed franking, that the editor has not seen anywhere else
This is another local letter franke correctly at 30 cents with a pair of the 15c Rhodes value with green overprint. This letter did travel through the mail as signified by the Hanoi Bak Bo arrival cancel on the reverse.
Adversity cover from Haiphong to Ninh Binh franked with a pair of the 15c Rhodes issue with black overprint. Transit cancels “Hanoi” on reverse. Correctly franked with 30c.
Here is a registered letter sent by the Asia Life Insurance Company to a client bearing the correct 90c franking on the reverse (made up of six 15c values with black overprint). The letter could not be delivered and so it was returned to the sender (see the black hand stamp “Return to sender” and manuscript remark).
A very similar registered cover sent on July 31st, 1946 within Hanoi also correctly franked with 90 cents (30 cents standard letter rate plus 60 cents for registration) made up of 6 of the 15c Rhodes value this time with the green overprint.
Registered letter mailed within Hanoi in February of 1946 featuring a blok of four of the 20C value plus a pair of the 5C value for an overall postage of 90C. 90 cents was the correct postage for a registered 20g letter at the time.
Rare combination of the 40c Douart de Lagree and 50c “Sport” stamp on a registered letter sent by the Asia Life Insurance Company. An attempted delivery of the letter was made on March 13th, 1946 and because it could not be delivered it was returned on April 15th, 1946 (as documented by two manuscript comments on the back). The front carries two hand stamps that state: “Phat Lan Chat” which means “Delivery Impossible” and “Gia Lai Nguoi Gui which stands for “Return to sender”. A French hand stamp which states “return to sender” was also added.
Registered letter mailed inside of Hanoi featuring a block of four of the 50C value over-paying the required registered letter tariff of 90C. So, either this letter was heavier than the standard 20g or was of philatelic origin.
Here is another registered letter sent by the Compagnie Franco American A’Assurance on January 26, 1946. It has an arrival cancel on the back date January 28, 1946. It is oversized and was much heavier than the standard letter rate allowed (original contents preserved). It carries a block of four each of the 15c value (black overprint), the 30c value with the rare 12:12 perforation as well as a pair of the $1 (1 Piastre) value for a total postage of $3.80. The latter is extremely rare on cover and would only have been used for such large/heavy letters or on packages. As a result most of them were discarded or did not survive the tropical climate.
You are more likely to find these stamps on philatelic products such as the one below that was produced by the “House of Then Wen”. It usually features a pair of the black-overprinted version of the 15c Rhodes value with a special cancel commemorating the 1st National Assembly on March 3, 1946. The envelopes were sold for $3 (3 Piastres) a hefty surcharge on the nominal of 30 cents. They also carry a cachet that states “Assembly of the People/Representatives of all the Nation in the Solemn Party/Opening of the First Reunion/Democratic Republic of Vietnam”.
Be careful. The special cancel above is sometimes offered on individual stamps as a fake. The fake cancel differs in many ways from the original and can be easily spotted by comparing the inscription “BUU 3-3 DIEN” . The letters/numbers on the fakes are much different from the originals above.
Favor cancelled un-addressed envelopes as seen below were employed to obtain cancelled versions of these stamps. Some postal clerks insisted on stamps being applied to a cover or piece of paper prior to cancelling them. Beware of covers were an address was added after the fact in order to simulate a postally used cover. Covers that travelled through the mail are always more expensive than purely favor cancelled covers.
Philatelic letter prepared by “Maison Vietnam Philatelique” using one of the 9 Hao HCM stamps along with some Viet Minh overprints. The letter was cancelled with the Hanoi Trung Uong Bac Bo canceller on November 8th, 1946.
Here are two examples of a cover and post card where it is more difficult to determine if they actually were transported through the post or if they were simply favor cancelled. Both items are hopelessly over-franked over the required tariff. The first is an adversity cover that was fashioned out of an old envelope “Societe Indochinoise Forestiere et des Allumettes” that was simply inverted. There is a cancel on the back but since it is identical to the one that was used to cancel the stamps it probably represents a favor cancelled item. The second is a picture postcard showing a rural village in Than Hoa (Annan). Since it was cancelled in Hanoi the card was also likely a favor cancel.
As in the 1st series of overprints these stamps found very little use. So cancelled specimens are always much rarer than mint ones. This is even true for cancelled to order items as the ones below. Just try to complete the set cancelled. It will take you years to do so.
If you are very lucky you will be able to acquire a booklet that was produced by a private company (Viet-Nam Philatelique in Hanoi) around the time when these stamps were issued. It contains the entire set of Viet Minh overprints plus the first Ho Ch Minh stamps issued in 1946 all in used condition. This item carries a running number 25 suggesting a low number of booklets prepared and a sales price at the time of $200 (200 Piastres).
With a little patience one can even find complete sheets of the mint or (rarer) CTO stamps: