South Vietnam, Foundation of the Culture Institute, October 27th, 1967, Michel Nr. SVN 393; A single stamp in a 10D nominal was issued in perforation 13.
Here is the mint stamp
and here the postally used stamp
This stamp was not officially released imperforate, however, a small number of imperforate trial proofs have come to market. Here is one of them.
Enpreuves de Luxe; STCV-Roma-membro del gruppo Thomas de La Rue, Londra inscrobed at bottom right.
Rare multiple franking of the 10D stamp (3) paying an overall postage of 30D on an international air mail letter sent on the First Day of Issuance from Saigon to Switzerland.
Registration Nr. 200740