The base of Louis' style was his crouch, which has sometimes been referred to as the Blackburn crouch, a name which I very much like. Jack Blackburn is an incredibly interesting figure in the history of boxing, having run a moderately successful career with almost 150 fights he wound up serving a prison sentence from 1909 - 1913 for murder. Blackburn was no doubt a controversial figure, which made the decision by Louis' early management to put Louis in the hands of Blackburn even more curious. Their main concern was to make Louis appear meek, mild mannered, and respectful - the anti Jack Johnson - yet a man who served time for murder was his closest confident. Blackburn not only nurtured Joe Louis, but abandoned his older, less athletic prospect, Jersey Joe Walcott, to do so.
Later in Blackburn's life, a young Sugar Ray Robinson began to attend Joe Louis' training camps and was reportedly the only one willing to go fishing on the lake with Blackburn despite having no interest in it. In his autobiography, Robinson recounts with a moving enthusiasm, how he used to accompany Jack Blackburn just to hear Blackburn talk about boxing. With Joe Louis, Jersey Joe Walcott and Ray Robinson all under the direct influence of Blackburn, it is arguable that his training produced the savviest stable of fighters of any coach to date!
One common feature of these three Blackburn fighters is their stance. While Joe Louis shuffled back and forth, Sugar Ray Robinson danced to his left all night, and Jersey Joe Walcott stepped across himself with either leg and turned his back multiple times in a fight, they all engaged in a very similar, technically excellent stance.
Notice in these two images of Louis (one seems to be southpaw, I'm unsure if it is mirrored, Louis rarely switched stances) how he carries his hips turned back - making his rear hand's path a long one but placing him almost sideways on. Additionally, he is bent forward at the waist - taking his head off of the centreline and making it very hard to reach with right hands. This means that his lead hand may be held lower - making it harder to see coming and adding power to it by linking it's motion more fully with the movement of his body. The tendency in many fighters who fight with their hands high is to jab from the arm alone - Louis, Robinson and Walcott all carried their lead and low and stepped in with their weight behind their jab.
Notice also that Louis' rear hand is not positioned up by his chin or cocked to punch, it is loose and free, ready to parry or check the opponent's lead hand. This is not laziness in the photos - Louis' rear hand was genuinely that relaxed, but it rarely stayed still for long. The truth of the Blackburn crouch is that offense from it is performed mainly with a stiff jab - but this is led by an active, adaptive right hand. Louis would parry his opponents jabs, looking for openings, or cover their lead hand and step in behind a combination - or be ready to block inside a lead hook and tie his opponent up. Take a look at the first few minutes of Louis' match with Nathan Mann.
Here is a nice example of Louis on offense as he walks down Max Schmeling in their rematch. Louis plods towards the German who is stepping off to re-establish position elsewhere in the ring, then pounces on him with a hard jab that comes unexpectedly soon. While it is a fairly fast jab, it is important to the remember that jabs with the bodyweight behind them, as with Louis', are often slower than "snap jabs" performed with the arm alone, and yet Louis connects this weighted jab completely by surprise. This is largely due to timing and the fact that Louis almost never left his stance - he was always in position to push off of his back leg and drive in with a lead.
Here, again in the second meeting with Schmeling, Louis uses his jab to enter the pocket. Notice that the Blackburn style, and Louis' style, is all about controlling with the right hand - rather than blindly firing the left with the right up by the chin as a guard. Louis covers Schmeling's lead and steps in with his own jab. His head is not as far offline as against Mann in this match, and that is largely to do with his following both jabs on Schmeling with a left hook, for which is it necessary to have the shoulders over the hips, rather than dipping as in Louis' usual jab.
The most important point of note in the Blackburn crouch is that the head may be taken out of the line of fire with a dip at the waist, and not with side to side head movement. In almost all of Louis' fights, he does not slip to his lead side - only to his rear side, in varying degrees of a duck. This movement comes from both the waist bending and the legs crouching. When a jab or lead hook is ducked, a counter may be fired with the right or left hand, and when a right hand is ducked, it is simply underhooked and a clinch is established.
Louis' style is often attributed to natural skill, but in fact he was a clumsy gentleman with a big punch who was turned into one of the finest boxers in history. The Blackburn crouch, whose defense requires none of the split second timing necessary to identify a punch and slip to the appropriate side, is absolutely a viable option for almost anyone. Side on stances are not the fashion at the moment in boxing, which very much moves in trends, but it is very interesting that men such as Floyd Mayweather and Bernard Hopkins can have such great affect by using so called "old timer" techniques in a sport which pretends it has evolved past greats like Joe Louis and Ray Robinson.
To witness some of Louis' excellent ducks and counters, and for a taste of some of the beautiful technique to come in this series, take a look at this excellent highlight by Reznick. Notice that when finishing, Louis can get a little wild - he is certainly not perfect, but his defense and counters are top notch and all depend on varying degrees of a duck to his right. Louis almost never slips to his left because it is simply not the nature of his stance. My personal favorite and a lead to counter that I enjoy utilizing a lot comes at around 2:30.
To learn more about Joe Louis, stay tuned on Fights Gone By, also pick up my Advanced Striking ebook if you haven't already - which contains 70 techniques from 20 great strikers, around 15 of which came from Louis, Walcott and Robinson alone. The Blackburn crouch is extremely important to my personal striking philosophy and so will be covered in great detail in my upcoming Kindle book, Elementary Striking.