My friend sent me a link to this the other night at 5am. I think we need a deck of these at the VC HQ, in times when mental breakthroughs are needed. The new 5th addition is out. I'd try to describe them, but it seems pages have been written on every possible meaning. Gregory Taylor on rtqe.net has been doing a lot of work on The Oblique Strategies.
The Oblique Strategies are a deck of cards. Up until 1996, they were quite easy to describe. They measured about 2-3/4" x 3-3/4". They came in a small black box which said "OBLIQUE STRATEGIES" on one of the top's long sides and "BRIAN ENO/PETER SCHMIDT" on the other side. The cards were solid black on one side, and had the aphorisms printed in a 10-point sans serif face on the other.
The deck itself had its origins in the discovery by Brian Eno that both he and his friend Peter Schmidt (a British painter whose works grace the cover of "Evening Star" and whose watercolours decorated the back LP cover of Eno's "Before and After Science" and also appeared as full-size prints in a small number of the original releases) tended to keep a set of basic working principles which guided them through the kinds of moments of pressure - either working through a heavy painting session or watching the clock tick while you're running up a big buck studio bill. Both Schmidt and Eno realized that the pressures of time tended to steer them away from the ways of thinking they found most productive when the pressure was off. The Strategies were, then, a way to remind themselves of those habits of thinking - to jog the mind.
It is not clear from any sources I've run across whether the cards were explicitly intended to be oracular at the outset - that is, whether or not Peter Schmidt and Eno necessarily saw them exclusively as a "single instruction/single response" kind of "game". The introductory cards included in all three versions of the first versions of the Oblique Strategies suggest otherwise. It seems clear, also, that the deck was not conceived of as a set of "fixed" instructions, but rather a group of ideas to be added to or modified over time; each of the three decks included 4 or 5 blank cards, intended to be filled and used as needed.