As always ***SPOILER ALERT***
I recently read an article which quotes Mark Gatiss stating that fans have missed "blindingly obvious" clues about where the show is headed. This of course got me thinking about what we all could have missed that was so obvious. Then, as I was cleaning my shoes just now, I was reminded of Carl Powers, and something struck me.
Carl Powers was the owner of the shoes Moriarty gave to Sherlock in "The Great Game." In 1989, Carl Powers drowned while in London for a swimming competition. Sherlock, after remembering the case from his boyhood, is able to determine that his death was not an accident, but rather murder.
How did Sherlock know the shoes were important back in 1989? He states that no one, except him, cared about the shoes. How did he know the shoes were missing? When telling Watson about Carl Powers, he tells him he read about it in the papers. However, he did not say that is the only place he got his information. If the no one cared about the shoes, the papers would not have bothered to report that bit of information. Sherlock, therefore, had to have gotten his information elsewhere. In order to figure out where young Sherlock got his information, let's explore where Sherlock was when Carl Powers was killed.
Carl Powers was killed in London, but that is not necessarily where Sherlock was when this event took place. Besides the London newspapers, what other newspapers would report on the child's death? The newspapers in Carl Powers' hometown would report on the story. In "The Great Game," it is revealed that Carl Powers lived in Sussex, Brighton to be specific. So, we can assume newspapers in Brighton would have reported on the death of Carl Powers.
Sherlock, therefore, grew up in the same area Carl Powers did. The only direct reference in the Sherlock Holmes Canon to where he grew up is in "The Greek Interpreter" where he states, "My ancestors were country squires." There really is no logical way to determine based on that statement where he spent his boyhood. However, this article published in 1999, more than a decade before the BBC show debuted sets forth a convincing argument that Sherlock Holmes is from Sussex. It is incredibly likely that two Sherlock Holmes nerds like Steven Moffat and Mark Gatiss would have read The Homes and Watson Report where this article was originally published.
Sherlock knew about the shoes because he knew Carl Powers and knew how much he loved those shoes. When those shoes were not brought back to Sussex after Carl's death, Sherlock became suspicious.
Moriarty confesses to the murder of Carl Powers to Sherlock, claiming Carl Powers made fun of him. Therefore, Moriarty knew Carl Powers.
Sherlock knew Carl Powers, and Moriarty knew Carl Powers. Is it possible that Sherlock and Moriarty have known each other for longer than we have all been lead to believe? In the RadioTimes article I linked to above, Gatiss also states that Season 4 deals with things they have been setting up for years. Is it the boyhood connection between Holmes and Moriarty?