My first exposure to “size doesn’t matter” was jujitsu. Except after about a year in Mark put it straight, “Anyone who says size doesn’t matter hasn’t fought someone sufficiently larger than them.” It’s true, size matters. She lied to you.
Judo and BJJ are both about the use of leverage. To quote Archimedes (the mathematician, not the owl from The Sword in the Stone): “Give me a lever long enough and a fulcrum on which to place it and I shall move the world.” Except that the length of the lever is limited by the length of the limbs and height of the individual applying the technique. As is the amount of force they can lever for the application. It’s simple physics. Given that, a known lever arm with a set amount of force on one side can at most apply a set amount of force.
So leverage has a maximum effect, but Kyuzo Mifune and Helio Gracie were each short, frail, weak, and are considered gods of the sport. Mifune threw a sumo wrestler with uki otoshi. Gracie has famous fights with men twice his size (with whom he draws). There’s no way someone who’s 5’2″ and 100 lbs can leverage enough force to throw a 240 lb individual. Right? I’d assume so. As frail as he is it’s not like his legs could support that much weight. He’s not an Olympic weight lifter with a serious squat. Uki otoshi doesn’t have you support the weight of the other person though. You’re just taking advantage of their existing momentum with expert execution. It’s a terribly difficult throw, I’m not going to lie. To be honest, I don’t think Mifune could use harai goshi on a sumo wrestler. Nor do I think he would even be able to hold down the 240 lb individual if the fight had to continue on the ground. I also don’t think controlling a much larger opponent to a draw is a moral victory or a sign that you can negate strength. Go for an infinite time and technique will get sloppy as you get tired. Yes, strength wanes too, but that doesn’t change the fact that he’s still twice your weight and you have to move that.
Now that we’ve introduced two small guys famous for the use of judo techniques, let’s spend some time playing history. Kyuzo Mifune was born in 1883 (one year after Kano founds the Kodokan). He joins the Kodokan in 1903 and by 1912 he’s a sixth degree black belt who’s tearing people new holes so well that he gets the nickname the “God of Judo” and has a reputation for being undefeated at the biannual Red and White Kodokan tournament. When Kano dies in 1938 Mifune becomes the most influential instructor in judo. At a whopping 45 kilos it’s not like the guy was tearing through people with strength. Helio Gracie was born in 1913, a year after Mifune gets his 6th degree black belt (the judo rank Gracie himself is credit as having achieved). In 1917 Carlos Gracie starts learning judo. When he was 16, Helio finally taught his first class. So we’re looking at like 1930. We know by 1912 Mifune had adapted judo for the use by a small man. Gracie realizes judo (as he learned it) won’t work for a small man and starts adapting it. BJJ is born.
By the way, if you ask most BJJ players they will tell you judo requires strength because they learn the story of Helio Gracie. This ends up offending pretty much any judoka who just mumbles to themselves that Mifune was two decades Gracie’s predecessor and had no trouble applying it to large opponents. You can’t say that BJJ is the only jujitsu and that Japanese jujitsu wasn’t made to work for small people. The subset Gracie learned wasn’t suited for small men. He wasn’t learning at the Kodokan with a variety of individuals of varying sizes and skill sets. The truth is both arts emphasize the use of leverage and technique over size and strength, but they approach grappling from two different sides. Judo is a top game. BJJ is a bottom game. I’d also like to point out that direct comparison is hard given the huge difference in rules. If both are practiced under some neutral rule set they will look more or less identical. If you put BJJ in an environment with judo rules where you can win by throw or pin, it will emphasize top game and end up morphing into judo. As we saw with Kosen, if judo can pull guard it’s much easier to do so and just fight on the ground than work for years practicing and perfecting 60 different throws.
If we are going to tell ourselves and our students that size doesn’t matter, we should be honest about it. “Size doesn’t matter given a sufficient gap in skill.” I’m not about to say something as stupid as there’s no one skilled enough to make up for huge gaps in size. Kyuzo Mifune, Helio Gracie, Caio Terra; people exist who despite being so small can fight very large individuals. But let’s be honest with ourselves, how many of us are Caio Terra? How many of us could walk into the Kodokan with no experience and within a year and half be a black belt? Individuals exist who defy the concept that size matters, but how many of us are at our size prepared to fight a D1 wrestler at 257 lbs? How many of us are even prepared to fight an absolute which would require going to the submission with no time limits?
I’m not saying there aren’t those who are as gods walking among mere mortals in the grappling world. What I am saying is most of us aren’t them. The challenge of size can be overcome with sufficient skill, but that doesn’t mean size doesn’t matter.