This is a story about the U.S. Marine Corps, the Rule of 3, and how to avoid getting overwhelmed

It's also about the first article I ever remember reading in Inc. magazine back in 1998 -- and how that simple rule has served me well and helped me accomplish my goals for more than 21 years.

The article was headlined "Corps Values," and it asked this:

The U.S. Marines are trained to make split-second decisions based on incomplete information, in life-or-death situations. Can they provide clues to running a faster-reacting business?

Here's the part I remembered almost verbatim, even before looking it up to write about it today:

In a nutshell, the rule is this: Each marine has three things to worry about. 

In terms of organizational structure, the "rule of three" means a corporal has a three-person fire team; a sergeant has a squad of three fire teams; a lieutenant and a staff sergeant have a platoon of three squads; and so on, up to generals.

The functional version of the rule dictates that a person should limit his or her attention to three tasks or goals. When applied to strategizing, the rule prescribes boiling a world of infinite possibilities down to three alternative courses of action. 

Anything more, and a marine can become overextended and confused. The marines experimented with a rule of four and found that effectiveness plummeted.

There are three reasons why this has stayed with me so long. (Yes, three!)

The first reason is the Rule of 3 itself. I've used it almost automatically since reading that article. I've found that for me too, three is the maximum number of things I can focus on at once.  

Right now, for example, I have three professional projects:

  1. my work for Inc.,
  2. a new publication I'm launching called Understandably, and
  3. a digital technology product that I'm developing with a colleague. 

More projects than that would just be too much.

The second reason I remember it so well is simply because it was in Inc. magazine. I've been a loyal reader going back many years. I'd started a couple of small businesses by then, but this publication was a big way that I stayed connected to my entrepreneurial dreams in those days. It's pretty wild to me that I write for it now. 

Finally, there's how I happened to have read it: I had just moved to Washington for my first job as a lawyer. My brother had just gotten out of the Marines and was living with me. And it was my dad who gave me the magazine with this article on the cover: He and my mom were visiting, and it was something to read while I was waiting for them at their hotel.

It's not just the Marine Corps that recognizes the Rule of 3. More recently, my colleague Jessica Stillman tackled it from a different perspective: "Work, Sleep, Family, Fitness, or Friends: Pick 3." 

And throughout history, great communicators have known that the Rule of 3 makes messages more memorable -- and sometimes even funny. It's the linguistic theory behind everything from "Veni, vidi, vici" to the Three Little Pigs.

Since this article stayed with me so long, I thought I'd reach out to its author, David H. Freedman. He told me the story led to him writing a book called Corps Business.

Glad you reached out. Funny, and of course gratifying, that you remember that article. [It] came about when I was visiting in-laws, and went out for a jog with my brother-in-law, who was a captain in the Navy Reserve.

Knowing that I wrote for Inc., he told me I should write an article about Marine management wisdom, and as an example he gave me the rule of 3. I was sold on the spot, and contacted the Marines soon after.

It's a simple rule, it's easy to remember, and I think it's truly helped me stay focused. Hey, what do you know--that's another list of three.