Our identified oldest porcelain: a Vincennes Tasse Litron

We bought two important pieces to Dorita last Friday. She had a lot of different porcelain cups in around U$ 15, most of them Czech. One of our collector friends was there and bought most of them but not the only one that I was interest in, sure because it was not marked. In fact there was another unmarked that also attracted my attention, but the rim of the plate had three flakes. So finally Sergio bought a Berthelemy Ivory sculpture and I this precious cup. At the beginning I was not even sure if it was old because of the ground color. I knew it was a Tasse Litron and confirmed this suspicion with the post of David under his nick of antiquarium http://www.collectorsweekly.com/stories/121988-rare-antique-french-porcelain-cup-tass
The cup has the typical carré (square) dimmensions (6cm x 6cm) and the soucoupe (saucer) that has the typical shape of a plain bowl (13cm x 3cm). In an interesting paper here http://www.bernardaud.fr/fichiers/depositaires/catalogue_amr/AMR-Tasses-histo.pdf you can read a little of their history. There it is said that “Cette tasse apparaît à la manufacture de Vincennes en 1752, alors que la consommation du chocolat, du thé et du café commence à se répandre. Lorsque les tasses à thé et à café se différencient au début du XIXe siècle, la tasse litron devient tasse à café, donnant lieu à une pratique restée en usage jusqu’au début du XXe siècle, celle de verser un peu de café dans la soucoupe pour le refroidir avant de le boire !” My personal translation is this: This type of cup was created by the Vincennes (the initial Sevres) in 1752, since the use of chocolate, tea and coffee was beginning to be popular. Then in the early 1800s, the cups for tea and coffee differentiated and the Tasse Litron was the one for coffee, and permitting an habit that continue till the beginning of the XX century: to pour a bit of coffee in the plate to cool it before drinking!
I remember 50 years ago to see my grandfather (the polished one the father of my mother) to drink in this way.
The biggest surprise was that when Sergio clean it up he noticed an incised marked (third picture). Searching I found it easily: Jean-Jacques Bachelier http://www.orientalceramics.com/index.php/product/vincennes-c-1751-1757-french-biscuit-porcelain/ an script JB

So my little and rare cup is older than I thought from 1752 to 1756. To my knowledge the colors are those of petite feu and they are look so contemporaneous. If you make the pictures to their full size you can see the rare technique of the enamel. The internal circle in the base of the cup has almost disappeared because of the use. The base of the cup has a flake.