The term Plein Jeu (�full chorus�) originated in the classical French organ (c1650-1790), and at that time was not a stop but a registration consisting of principals, flutes, Fournitures, and Cymbales, rarely containing any 3rd-sounding ranks. Douglass calls it �sine qua non of the instrument�. Here is what Dom Bedos has to say about it: The Cymbale always accompanies the Fourniture: these two stops are never separated, and together they are called the Plein-Jeu. In a 16' organ, the smallest possible Plein-jeu is nine ranks: the upper five ranks of the Fourniture, and the upper four ranks of the Cymbale. An 8' organ requires a Plein-jeu of seven ranks: four and three, respectively. An organ with 32' open and stopped ranks takes a full Fourniture and Cymbale. An 8' Positif takes a seven-rank Plein-jeu; if there be no 8' open stop, the Plein-jeu will have five ranks; the upper three from the Fourniture, and the upper two from the Cymbale. A four- or three-rank Plein-jeu is drawn from the Cymbale only; an eight- or six-rank stop is taken half from each. Not all builders follow these methods and progressions exactly. Some do not begin the first rank of a nine-rank Plein-jeu with a 4' pipe, but rather with a 2-2/3'. Some do not make all the ranks of a full compass, but they omit an octave or more in the treble, so that their Plein-jeu may have nine ranks in the bass, but only seven, six, or five in the treble, etc. ... all builders agree that fifths and octaves only should be used, and never thirds. The richest tone in the organ, according to experts and connoisseurs of real tone, is the Plein-jeu blended with the foundation stops which support it in the correct proportion. The mixture called
Osiris lists over 250 organs containing one or more Plein Jeu, ranging from II to IX ranks. The earliest examples are by Clicquot.