Motley Fool co-founder David Gardner has been doing his Rule Breaker Investing podcast for two-and-a-half years now, and while he might wish that his fans listened religiously to every one, odds are that there are more than a few current listeners who haven't heard everything he's had to say so far.

So, in this episode, he's kicking off a new occasional series: Blast from the Past. He'll pick five points to revisit that he's discussed in previous shows -- ones he views as particularly worth a listen, whether you're getting a refresher or hearing them for the first time. In this segment, he travels back to March 2017 and shares his thoughts on how often the odds-on favorite gets taken down by the surprising upstart, how they pull it off, and what we can learn from those upsets.

A full transcript follows the video.

This video was recorded on Jan. 23, 2018.

David Gardner: Blast From The Past, No. 4: Well, this one was inspired by @HodaMehr, one of my Twitter  friends. Hoda said, "David, did you see that John Malkovich video before the football game on CBS last weekend?" Now, I know there are a lot of football fans, American football fans listening who know what I'm talking about; about a four-minute video that was incredibly well done and well produced. All the way self-effacingly humorous when you've got John Malkovich, but also always stirring, because John Malkovich can really rile any viewership.

He does a beautiful job, and they had a lot of fun with the idea that what you're about to watch, the football game you're about to watch, is a classic David vs. Goliath scenario. And by the way, just google John Malkovich, NFL. If you didn't see it, you could watch the four-minute video. It's so well done. I recommend it to your attention.

Anyway, Malkovich throws away the script that he's been given. It's overwritten, and poorly written, and he just spontaneously ad libs how really to cast a David vs. Goliath tease for an upcoming broadcast. It's beautifully done, and Hoda, thank you for noticing it. I liked it, too.

One of the ironies, now looking backwards just a few days later, is that as it turns out, David lost that football game. It was an excellent football game between the New England Patriots and the Jacksonville Jaguars. The Jaguars were the David, and they had the lead 20-10 and gave it all away at the end. So, Goliath won that one, which I think is not really the point of David vs. Goliath.

Anyway, Blast From The Past, No. 4. March 22nd, 2017. The title of our podcast that week, How David Beats Goliath. And I was reacting at the time to a wonderful Malcolm Gladwell article that he originally penned for The New Yorker and then turned it into a book in which he talks about how David actually does beat Goliath.

So, I highly recommend that podcast to your attention. That's an easier one to find because it's less than a year ago. And, of course, if I summarize too much this podcast will be far too long, so I'll just tease you with a couple of the key insights about how David really does beat Goliath.

Gladwell cites a military database that's gone back through human history and identified all military encounters that we are aware of, and ones in which one side has a 10x advantage on the other. Ten times the force. Maybe, surprisingly, the Goliath, the 10x side, wins 72% of the time. Now, the reason it's a surprise is because I think most of us would assume it's about 95% or 99% of the time. It turns out it's 72% of the time. So, good news. When you greatly outnumber your foe, you do win more often than not, but pretty surprising that 28% of the time, historically David finds a way to beat Goliath.

Gladwell goes on to point out if you filter for when the underdogs had these conditions in place before these battles [a] they knew they were the underdog [b] they acknowledged that they were the underdog and [c] they adopted an unconventional approach because they were the underdog. Amazingly, filtering that military database, the underdog, David, then wins 63% of the time. The majority of the time. David stops looking so much like a David when you hear those numbers.

So, Gladwell goes on, and I do in this podcast, of course, go on to unpack that some, talking about a few key traits that are in place when David is beating Goliath. I already tipped off one of them -- taking an unconventional strategy.

A second trait, often in place, is that it will be adopted by an outsider. Not one of the insiders. Not one of the cool kids, or the favorites. Enjoying them, as I am right now, AMC's TURN on Netflix. I'm about midway through Season 1, looking back at the American Revolutionary War. We can think about I don't know that the British were 10x-ing Americans. I don't know how the military database reads that one, but one thing's for sure. The Patriots were the underdog at the time, but that outsider mentality often can unite people in a way that being one of the cool kids or insiders doesn't, as effectively.

And finally, Gladwell points out that not knowing the conventions of how a game is normally played can turn out to be an advantage. Now, of course, in that podcast, I talk about how that's whatRule Breaker Investing does. After all, we have adopted an unconventional strategy to beating the market, something a lot of people think you can't do [beat the market]. We're often buying what people consider to be highly overpriced stocks. We're often getting into them before the mainstream. And then, maybe ironically again, we're continuing to hold them well past most of the mainstream.

This approach has been adopted by outsiders. You and me as fellow Fools -- we are from Main Street. I don't have a background in Wall Street -- you may not, either -- but here we are as common Fools, outsiders, beating the market and not knowing the conventions, sometimes, of how the game is supposed to be played turns out to be an advantage.

A lot of people think you have to read Benjamin Graham and be well steeped in Warren Buffett even to go ahead and invest on your own, whereas I, myself, have never read a book about Warren Buffett. I greatly respect the man. I've made that clear in the past on this podcast. I've dedicated an entire Great Quotes, Vol. X to just Buffett quotes on their own. But, really this whole approach that we're taking is the outsider's view. Perhaps, ironically, I can have fun with the idea that it's named when "When David Beats Goliath" and you, along with me.

Anyway, that article, and then the podcast, I've got a few great storytelling examples. Of course, Gladwell, the consummate storyteller, telling an incredibly great story about a girls' basketball national championship. I don't have time for that now.

I will briefly mention another example he gives, which is a military naval [simulation] in the 1980s. An outsider who is kind of a computer geek shows up at a weekend competition sponsored by the military. A serious one that has you selecting -- basically paying points -- to build your own naval armada, and you and I are going to go head-to-head in a computer simulation to see who wins.

You have people from the military. You have very serious military strategists -- people steeped in history -- at this competition. And I believe a computer professor [his name is Doug Lenat] shows up and out of nowhere beats everybody by using a completely unconventional strategy. In his case, rather than buy some aircraft carriers, and then some battleships, and some destroyers, and some smaller boats, and having a diverse mix of naval capabilities; Lenat and his algorithmic routine that he developed called Eurisko [I love this story] teaches him simply to spend all his points on PT boats.

Now, PT, as you may or may not remember, is short for patrol torpedo boat. PT boats. So Lenat just spends all of his points on PT boats, sits them there without moving, and as every other competitor faces him [again, some very serious people with serious resources behind them that weekend], his PT boats just go and shoot down what's coming at them. And when he loses a dozen or 50 of them, even if they go down, they're cheap losses. From a human dynamic, it's sad to think that you would lose anybody, but from a grander campaign view, these are losses you can abide, and as it turns out, that PT boat strategy won hands down.

In fact, in 1982, a year later, those who sponsored the competition changed the rules so that Eurisko couldn't come back and play the same game. They said, "You actually have to have fleet agility." There were some new rules put in there, and so Lenat reprogrammed Eurisko, which told him to still buy the same PT boats, but for this competition, in order to up his fleet agility, he had the PT boats, after they fired, sink themselves. And in the game rules he was playing by, that was enough to up his so-called fleet agility and, sure enough, he showed up with Eurisko and won again.

So, unconventional strategies adapted by outsiders often who don't know the conventions of the game; that turns out to be an advantage and David beats Goliath.

David Gardner owns shares of Netflix. The Motley Fool owns shares of and recommends Netflix and Twitter. The Motley Fool has a disclosure policy.