What is the 70 30 rule Warren Buffett?

Could you please elaborate on the "70-30 rule" attributed to Warren Buffett? I'm interested in understanding its significance and how it applies to investment strategies. Could you also provide some context behind this rule and maybe an example to illustrate its practical application? I'm curious to know if this is a widely accepted principle in the investment community and how it fits into Buffett's overall investment philosophy. Thank you for shedding some light on this intriguing concept.