Why Chance? (written in 1983)
The short answer is that it fascinates me. I am constantly amazed by the solutions which chance throws up—ideas which I would not have reached without it. It is probably important to point out that my use of chance varies from that of the father of chance music: John Cage, in a fundamental aspect. Cage was concerned to remove his own personality from his music. Nothing could be further from my own aims. Most of my music expresses my own feelings very strongly, and the chance systems I devise are always intended to serve that purpose. If such a system were to produce material, which I did not like I would feel free to reject it. Curiously, however, this almost never happens. I came to chance music as with almost everything else innovative that I have tried, through working with children. I invented chance systems to help them write their own music and was struck by two unexpected aspects of it: The pleasure I had in inventing the system itself and the opportunity offered to see the composition as a whole from a distance. The first aspect I found so interesting I even had the feeling I was cheating the children of the most pleasurable part of the composition process.
Normally one envisages a sound and works directly with the notation to produce this sound. Using chance one imagines the sound and then creates a chance system, which will produce it. Naturally one can start with only a very approximate idea of the final sound, and this system supplies the fine detail. The ability to imagine roughly what one wants brings me to the second point. It presupposes that one must stand back and look at the composition from some distance. This is something, which is so difficult to do using traditional composition processes. Here then I had a system which was not only supplying the detail of my composition, but was also allowing me to see it with a much more convenient perspective.
This was just the beginning, I was supplying the form and the chance process the detail. Later on I was to invent other chance systems, which also supplied the form: Piece of 4 and Three Chance Pieces Plus One.
There is probably an even more important side of composition by chance: the psychological effect on the composer. It gives one seriously to think, how one's own brain functions; How does it make decisions? No doubt this is a rather naive view of brain physiology, but I have the feeling that under normal circumstances the brain is faced with such a bewildering number of possible solutions to choose from that in self defence, as it were, it chooses the sort of solution it has always chosen—we call this a ‘rut’. By letting this sort of decision be made by a die or some other chance instrument, one is slowing this selection process down, (I imagine the brain scanning with the speed of a computer, but unlike the computer, able to be affected by the complexity of the operation) and forcing the composer to accept one random solution. In general this solution will be quite different from any made by any compositional school in the past and different from the work of the composer himself which has obvious advantages if one is interested in making an original statement. As I have already said, I am constantly amazed at the interesting nature of the chance solution and almost never change it. This has a wonderfully positive effect on me personally. Not only am I producing music in a manner, which I find exciting. I am also being stimulated by the results. This is not to say that the whole process is any easier than traditional methods. The laborious creative work happens at a pre-stage” in planning an appropriate system within which choice may work. The stimulation comes if this is well done and the normal laborious process of working on detail at close quarters proceeds more rapidly and in a manner refreshingly different because of the constant surprises chance produces.

The following is the text of a radio talk prepared as an introduction to the Three Chance Pieces for Piano and recorded at Kent House, Christchurch in December 1983. (N.B. This was written before the composition of “Plus One”)

Three Chance Pieces for Piano Kit Powell (1981)
For some years I have been fascinated by the surprises offered by chance systems which I have invented to control certain aspects of some of my works. These surprises have had a liberating effect on my own creativity so that I had the feeling of having discovered a “refresher” agent a lifting-me-out-of-a-rut device.
In Three Chance Pieces for Piano (the ‘Plus One’ had not been written as I wrote this text) I wanted to take this use of chance a step further. Instead of chance controlling just some aspects of the pieces, I wanted it to control almost all of them. It is important to add at this point that my use of chance is fundermentally different from that of the Father of Chance Music: John Cage. Whereas Cage uses chance to remove his own emotional involvement from all decision making, my chance systems are specially designed to produce preconceived emotional ideas. Thus I see my role in writing my sort of chance music as being the composer of a system within which chance can operate. I am still emotionally involved with both the process and the outcome, but because of the presence of chance, an infinity of outcomes is possible from each system I invent.
I would like to explain briefly some aspects of the chance systems used in these piano pieces—(N.B: this was before the computer era and I was dependent on dice as generators of chance-numbers).
The building blocks of all pieces are called pitch cells. The number of notes in each cell and the pitch of each note was determined by chance. There are six pitch cells—there were six of all parameters so that I could use dice, just transpositions of the pitch cells needed a toss of a coin as well—heads meant the die-number plus 6:

These were created by chance (3 – 7 notes) and then placed in the shapes:

Chance decisions were made about Register: low, high, low and high converging, etc., and about Duration - numbers were taken from the Fibonacci Series: 1, 2, 3, 5, 8, 13, 21, … for the duration in seconds, and finally chance decisions were also made among a choice of rhythmic shapes (or Motives).

The first three bars of Chance Piece 1 were made like this:

  • bar 1: Register 6, Shape 6, Pitch Cell 5, Transposition 11, Duration 3
  • bar 2: Register 6, Shape 3, (shape three is empty with a duration 13 seconds)
  • bar 3a: Register 4, Shape 1, Pitch Cell 3, Transposition 0, Duration 1
  • bar 3b: . . . . . . . . , Shape 5, Pitch Cell 3, Transposition 3,

Depending on the duration it was sometimes necessary to roll dice for several shapes and pitch cells.

Chance Piece 2

The three shapes (Fig. 4:7) were chosen with a “weighted” probability:

  • shape 1 with a probability of one third, if I rolled 1 or 3
  • shape2 with a probability of one half, if I rolled 2, 4 or 6
  • shape3 with a probability of one sixth, if I rolled 5

For all three shapes I needed three random numbers:

  • p (pitch cell, 1-6),
  • t (transposition, 1-12) and
  • r (number of repeats, 1-6).

For shapes 2 and 3 I needed an additional p (pitch cell) and t (transposition) for the “crotchet-melody” (shape 2) and for the “chord” (shape 3).

The shapes produced by chance were:

  • 1 1 2 1 2 1 2 2 1 1 2 1 3 2 1 3

Bar 1: I drew the numbers: 2, 8, 3, that is, the second pitch cell, eighth transposition, 3 repeats (Fig. 4:3)

Bar 2: I drew the numbers (5, 9, 6) (Fig. 4:4): to which the cell (1, 5) (Fig. 4:5) would produce a melody (Fig. 4:6).

Bar 3: (1, 2, 2)

First four bars of Chance Piece 2:

* * * * * *

Piece 3

The construction of this was similar to that of Piece 1 but with a faster tempo.

Plus One (1984)

As mentioned before, the composition of “Plus One” includes all the previous systems. The selection of system 1, 2 or 3 was made with a new chance system, “weighted” so that the probability of elements of “Chance Piece 1” appearing in the first third of this new piece, and of “Chance Piece 2” in the middle third and of “Chance Piece 3” in the final third was much higher.

A new element Chord, (heard first at the beginning of “Plus One” – marked in yellow below) was also allowed to occur once, twice or three times at random during the piece.

Yellow: derived from Piece 1 (Tempo 1/4=120) Blue: derived from Piece 2 (Tempo 1/4=60)  Red: derived from Piece 3 (Tempo 1/4=144)
Yellow: derived from Piece 1 (Tempo 1/4=120) Blue: derived from Piece 2 (Tempo 1/4=60) Red: derived from Piece 3 (Tempo 1/4=144)

Works using chance procedure:

  • Devotion to the Small
  • The Ever-Circling Light
  • Piece of 4
  • Three Chance Pieces Plus One
  • Snakes and Ladders
  • Les Episodes
  • Piano Poems
  • Kapiti
  • Chance Piece for Flute and Tape
  • Microzoic Piano Piece
  • 5 Short Chance Pieces for Piano