Jeux 6 is an example of a form frequent in the music of Haubenstock-Ramati, that of the “mobile”. The term is borrowed from sculpture where it describes a particular kind of work. The artist creates a number of constituent shapes but stops short of fixing a final overall form for his work. Instead he arranges it in such a way that the component parts move individually, providing a constantly shifting pattern. The sculpture is in a sense “finished” since all the component parts themselves are complete but it has no fixed form.
The musical equivalent has a number of completed sections whose order is left to chance in some way. Normally this is done by dividing the music into squares or areas, whose ordering is left to the performer. He may need to plan this in advance, or in consultation with other players, or it may be left to the spur of the moment. Some pieces in mobile form impose restrictions on which parts may be played together or even make the manner of performing a given part dependent on the particular part which preceded it.
In the case of Jeux 6, Haubenstock-Ramati uses a grid of sixty squares, each containing a fragment of music or a silence of specific length. Each player individually works his way over all sixty squares, beginning with any one of ten nominated squares and “reading” the grid as a series of horizontal, vertical or diagonal lines. When he reaches the square on which he began he has completed a “cycle” and the whole piece is made up of two such cycles. Each player plays exactly what the composer wrote and (after making the initial choice of direction) in the order the composer dictated yet the effect of 6 players doing this separately is that no two performances could ever be identical.
Each of the six percussionists has a collection of instruments made up of the same types. Firstly he has ten wooden or drum instruments: three tom-toms or bongos; one timpanum; one larger drum; and five wood or temple blocks. Secondly he has one melodic percussion instrument, a Vibraphone or tubular belle for instance: lastly he has six metal instruments: two suspended cymbals; a gong; a tam-tam; triangle and a smaller instrument such as a crotale.