How did Sherlock know specific personal information about John Watson when meeting him for the first time?

Question

How did Sherlock know all the specific personal information about John Watson in first episode of Sherlock? They don't meet before but there is a conversation quote between them:

Dr John Watson: We don't know a thing about each other. I don't know where we're meeting. I don't even know your name.

Sherlock Holmes: I know you're an Army doctor, and you've been invalided home from Afghanistan. I know you've got a brother who's worried about you, but you won't go to him for help because you don't approve of him, possibly because he's an alcoholic, more likely because he recently walked out on his wife, and I know your therapist thinks your limp's psychosomatic - quite correctly, I'm afraid. That's enough to be going on with, don't you think? The name's Sherlock Holmes, and the address is 221-B Baker Street. Afternoon.

Answer 1

Check out the complete conversation for your answer:

Source IMDB:

Sherlock Holmes: When I met you for the first time yesterday, I said "Afghanistan or Iraq?"

Dr John Watson: Yes. How did you know?

Sherlock Holmes: I didn't know, I saw. Your haircut, the way you hold yourself, says military. The conversation as you entered the room - said trained at Bart's, so army doctor. Obvious. Your face is tanned, but no tan above the wrists - you've been abroad but not sunbathing. The limp's really bad when you walk, but you don't ask for a chair when you stand, like you've forgotten about it, so it's at least partly psychosomatic. That suggests the original circumstances of the injury were probably traumatic - wounded in action, then. Wounded in action, suntan - Afghanistan or Iraq.

Dr John Watson: You said I had a therapist.

Sherlock Holmes: You've got a psychosomatic limp. Of course you've got a therapist. Then there's your brother. Your phone - it's expensive, email enabled, MP3 player. But you're looking for a flat-share, you wouldn't waste money on this. It's a gift, then. Scratches - not one, many over time. It's been in the same pocket as keys and coins. The man sitting next to me wouldn't treat his one luxury item like this, so it's had a previous owner. The next bit's easy, you know it already.

[indicates back of the phone, which has been engraved with the inscription "Harry Watson - from Clara XXX"]

Dr John Watson: The engraving?

Sherlock Holmes: Harry Watson - clearly a family member who's given you his old phone. Not your father - this is a young man's gadget. Could be a cousin, but you're a war hero who can't find a place to live. Unlikely you've got an extended family, certainly not one you're close to, so brother it is. Now, Clara - who's Clara? Three kisses says romantic attachment. Expensive phone says wife, not girlfriend. Must've given it to him recently - this model's only six months old. Marriage in trouble, then - six months on, and already he's giving it away? If she'd left him, he would've kept it. People do, sentiment. But no, he wanted rid of it - he left her. He gave the phone to you, that says he wants you to stay in touch.

Dr John Watson: How can you possibly know about the drinking?

[cuts to a close-up of the phone's charger port, showing obvious scratches around it]

Sherlock Holmes: Shot in the dark. Good one, though. Power connection - tiny little scuff marks around the edge. Every night he goes to plug it in and charge but his hands are shaky. You never see those marks on a sober man's phone, never see a drunk's without them. There you go, you see? You were right.

Answer 2

Sherlock was never a fraud. He was a smartass all the way, but everything he says is calculated and calm, unless there is something severely hard for him like John, trying to make him more socially acceptable. When he first meets John, John walks into the lab and stays standing even though there is a chair directly behind him. That means that he has some psychological damage, then he looks at the tan lines on his wrist. He still has the tan from the gloves he wore, which makes him a doctor. Those two are important together because there would not regularly be a damaged doctor. The only case in which this would usually happen would be the armed forces, because being a doctor is what damages them. From this he deduces that John has a therapist because most psychologically damaged war veterans get therapists. Then he sees the phone. On the back there is an inscription that signifies a relationship between a " Harry Watson" and Clara. The phone is expensive, so Harry and Clara are married. Sherlock sees that Harry is a sibling because the phone is a "young man's gadget" so it could not be from a uncle or father. They are both to young to have grown and married kids, so that is ruled out. Sherlock sees that John doesn't approve of Harry because he got the phone, which shows they Harry reached out to him, but John is still looking for housing. Then, Sherlock looks for the reason for the disapproval. At the place for the charging cord, there are scratches in the metal, like someone struggled with shaking hands to plug in their phone. That means that Harry was an alcoholic. Lastly, Sherlock gets that Harry left Clara because the phone was givin to John, and when someone is left they keep things for sentiment, but when you leave someone things aren't kept.

Answer 3

The answer is simple and can be stated with a single word: Observation. In A Scandal In Bohemia, Holmes says to Watson (during yet another scene where Watson is amazed that Holmes seem to know things supernaturally), "You see, but do not observe."

People often use Holmes to illustrate this key ability.

Answer 4

If you watch later in the episode Sherlock explains how he knows all these things; John's limp is psychosomatic as he doesn't wince in pain, he must have therapist since he has an imagined limp and a GP would have nothing physical to treat, he was in the army due to his posture, Afghanistan is due to his lack of tan/tanlines, his sister drinking is due to her hands shaking when she puts her phone on the charger and there are scratches around John's charger port, he has his sister phone as the inscription on the back is to someone named Harry not John so it's secondhand a gift. Harry is short for Harriet so Sherlock got John's sibling's gender wrong.

Sherlock sees and processes things incredibly fast - limps, tanlines, phones - all in a few seconds. It might seem fantastical but there are people who do this professionally. Everyone does it to someone degree of another, if you see someone in the street is shouting and bleeding you go help them but if they are also swearing, slurring and throwing punches in the air you call for help or the police.

Answer 5

Sherlock Holmes is an interesting man. He had an organised knowledge base for topics that might relate to his chosen line of work. (so pretty much everything socially acceptable.) so when specific details could give a hint he knew about it.said trained at Bart's, so army doctor.That line is a great example of him knowing things and keeping it organised. he knew people who trained at Bart's could be army doctors. so when he heard it he could identify the possibility. then he mentions "his haircut and the way he holds himself" which fall in line with the normal behavioral patterns of ex and current military. So he could confirm army doctor off that. next when he got the phone he reconised with the money problem Watson had there's NO WAY that was a luxury he bought on his own. so there had to be someone who gave him it. In the show you see Holmes casually look at the back of the phone for a split second and use an expression that shows interest, Finish the text and hand it back. that was all the time he needed to finish his observation.

Another example is in "The Blind Banker" the detective says "it's obviously a suicide that's the only explanation for all of the facts. Sherlock interrupts "wrong that's the only explanation for some of the facts you got an explanation you like and you're choosing to ignore any information that doesn't comply with it. Then goes on to explain the table on the left hand side of the sofa. The coffee mugs handle favoring the left side. the outlets habitually used on the left side. the tablet on the left side of the phone. the butter on the right side of the knife so left hand to spread." since he was left handed and the bullet went in the right hand side it shows an interesting disconnect between normal human behavior and this "suicide" so murder is a more likely solution.