Composed in April 1972 with a computer at the University of Cologne, this piano piece has a duration that I was only able to determine precisely in 2020 with the help of a computer. Although I have been familiar with computers and their programming since 1971, until now I had no access to one that could process very large numbers - the durations of my piece are expressed in seconds as the products of powers of two, those of -2215 (very short) to +97 (very long).

Sounds are given as note names. There are always pauses in between, which are shown as four connected hyphens. The durations of the sounds and pauses take the form N times a power of 2, e.g. the fourth event, a pause of 12 X 2^58 seconds. I was able to calculate a long time ago that this duration corresponds to 109,603,884,235 years, 35 days, 17 hours, 48 minutes and 48 seconds. The problem was adding up all 10,000 durations. Now it finally turned out that the total duration of the piece is 1,291,393,870,437,209,181,492,178 years, 182 days, 2 hours, 33 minutes and 46.361730597612109.. seconds.

Stochroma may be performed by any number of pianists in excerpts of any length. The title is made up of 'stochastic' and 'chromatic'. The name of Stockhausen, my composition teacher at the time (1972) is also in there.

In 2001, the composer Tom Johnson exhibited a score page in the Queen Sofia Museum in Madrid for several weeks.