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KISS principle

KISS, an acronym for "Keep it simple, stupid!", is a design principle first noted by the U.S. Navy in 1960. First seen partly in American English by at least 1938, KISS implies that simplicity should be a design goal. The phrase has been associated with aircraft engineer Kelly Johnson. The term "KISS principle" was in popular use by 1970. Variations on the phrase (usually as some euphemism for the more churlish "stupid") include "keep it super simple", "keep it simple, silly", "keep it short and simple", "keep it short and sweet", "keep it simple and straightforward", "keep it small and simple", "keep it simple, soldier", "keep it simple, sailor", "keep it simple, sweetie", "keep it stupidly simple", or "keep it sweet and simple"1.

Origin

The acronym was reportedly coined by Kelly Johnson, lead engineer at the Lockheed Skunk Works (creators of the Lockheed U-2 and SR-71 Blackbird spy planes, among many others). However, the variant "Keep it Short and Simple" is attested from a 1938 issue of the Minneapolis Star.

While popular usage has transcribed it for decades as "Keep it simple, stupid", Johnson transcribed it simply as "Keep it simple stupid" (no comma), and this reading is still used by many authors.

The principle is best exemplified by the story of Johnson handing a team of design engineers a handful of tools, with the challenge that the jet aircraft they were designing must be repairable by an average mechanic in the field under combat conditions with only these tools. Hence, the "stupid" refers to the relationship between the way things break and the sophistication available to repair them.

The acronym has been used by many in the U.S. military, especially the U.S. Navy and United States Air Force, and in the field of software development.1

Use in software development

  • Don't repeat yourself (DRY)
  • Minimalism
  • Unix philosophy
  • Arch Linux
  • Slackware Linux
  • Chartjunk
  • List of software development philosophies
  • Reduced instruction set computing
  • Rule of least power
  • There's more than one way to do it
  • Worse is better (Less is more)
  • You aren't gonna need it (YAGNI)

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  1. Scooped from wikipedia ↩↩