It's been a few months now since series three of Sherlock aired, which means we're back to the waiting game for who knows how long. With the waiting game comes rewatches, and with rewatches comes noticing things you previously missed, such as all of the references to Conan Doyle's canon. Reference hunting (new drinking game maybe?) is one of the best things about Sherlock Holmes adaptations, and creators and Holmes fanboys, Steven Moffat and Mark Gatiss, do not disappoint as they cleverly weave in tons of references every episode. Just like the two previous series', series 3 had many references and allusions to Conan Doyle's work, including the introduction of characters such as Mary Morstan, Charles Augustus Magnussen, and Sherlock's new protégé Wiggins, based on the leader of the Baker Street irregulars in the canon. Besides the more obvious references such as the titles, there are tons of smaller references that often go unnoticed. Keep reading to see what you may have missed...
20. The Yellow Face
Let's start at the beginning with Mofftisses Christmas present to everyone, Many Happy Returns. The seven minute prequel was filled with references to the canon such as the Trepoff murder case from A Scandal In Bohemia, Sherlocks visit to Tibet from The Adventure of the Empty House, and the ice cream deduction based from The Six Napoleons when Sherlock noticed the depth by which the parsley had sunk into the butter. However, one you might have missed is the brief showing of a yellow mask in the box from Lestrade, which is a clear reference to The Adventure of the Yellow Face.
19. Hat Deduction
As we see in The Empty Hearse, Sherlock and Mycroft love to play games with each other such as operation and even a little game of deduction. The game of deduction that the Holmes brothers play using the hat is an allusion to two different stories. The first is The Adventure of the Greek Interpreter, which is Mycroft's first appearance and has the Holmes brothers dueling it out in a game of deduction at the Diogenes Club. The Second story alluded to, The Adventure of the Blue Carbuncle, has Holmes deduce several facts about a man just from his hat that he dropped.