"Two chords" - Here's a quote from an article about Christy Moore:

Guthrie famously remarked that any one song with more than three chords was showing off, and Moore tends to favour an equally economical style of accompaniment.

"In my early days, I learned two chords", he told an interviewer in 1993, "and I only learned songs that could only be played to those two chords, C and G7 - and I would have to admit that 35 years later not a lot has changed."

(Actually I think what Woody Guthrie actually said was that two chords were enough mostly, and you only needed to put in the third chord when you wanted to show off and impress some girl in the audience.)