Ask comic fans the identity of the Joker’s greatest enemy, and they will rightfully say Batman, but while the Dark Knight may be unparalleled as a vigilante, even he'd admit that the Clown Prince of Crime has tangled with a better detective - namely, Sherlock Holmes! In 1976’s The Joker #6, the villain matched wits with, and was ultimately bested by, an actor who thought he was Sherlock Holmes. The story was written by the legendary Denny O’Neil, with art by Irv Novick and inks by Tex Blaisdell.
Since the Joker’s first appearance 81 years ago in Batman #1, he has been the Dark Knight’s greatest foe, returning with new and even more grotesque schemes every time, severely testing Batman’s “no-kill” rule. In 1976, the Joker was given his own solo title, which would run for nine issues. The series, written by some of the day’s top writers, including Elliot S. Maggin and Dennis O’Neil, saw the Joker either team up with or fight other DC villains; one memorable issue saw the Joker and Scarecrow throw down over their respective toxins. For issue six, the Joker fought the master detective Sherlock Holmes... sort of.
The issue opens at a dress rehearsal for a Sherlock Holmes stage play. The Joker, wishing to embarrass all history’s greatest detectives, robs the theater company, slipping in disguised as Moriarty. During the robbery, Clive Sigerson, the actor portraying Sherlock, is hit in the head. As a result, Sigerson thinks he really is Sherlock Holmes - and the Joker is Moriarty. Sigerson takes off after the Joker, but before he leaves, the play’s director tells a stage hand to follow the actor, and readers learn the stage hand’s name is Watson! The pair pursue the Joker, along the way referencing several classic Sherlock Holmes stories. Holmes and Watson eventually corner Joker on a yacht. Holmes hits the Joker with a high-pressure water gun, knocking him out and leaving him for the authorities. The issue ends on an ambiguous note: did Sigerson, as a result of brain damage from the concussion, think he was Sherlock Holmes, or was he genuinely channeling the character's core spirit?
Sherlock Holmes was the finest detective of his era, possessing a highly analytical mind and a keen eye for observation. Holmes was one of the many influences Bill Finger and Bob Kane drew on for the creation of Batman. It is easy to see why the Joker hates Sherlock Holmes - he sees so much of Batman in Holmes, he's compelled to humiliate him. But more than that, Holmes’ analytical mind is the antithesis to the chaos the Joker stands for - the Joker wished to humiliate Holmes by reenacting some of his most famous stories, but in the end, "Holmes" turned it back on the Joker, which ultimately led to his downfall.
It's also possible that the Joker somehow knows that the real Sherlock Holmes - who exists in DC Universe canon - has also acted as an ally of Batman, and is striking out as usual at anyone who the Dark Knight loves or respects. Sadly for Joker, even an imitation of Sherlock Holmes was enough to take him down, showing that while fighting crime doesn't have to mean being a better detective than Batman, it certainly helps.