After months of negotiation, Avraham, a Jewish scholar from Odessa, was granted permission to visit Moscow.
He boarded the train and sat down. At the next stop a young man got on and sat next to him. Avraham looked at the young man and thought,

This fellow doesn't look like a peasant, and if he isn't a peasant he probably comes from this area. If he comes from this area, he must be Jewish because this is, after all, a Jewish area. On the other hand, if he is a Jew, where could he be going?
I'm the only one from our area to be allowed to travel to Moscow.
Wait - just outside Moscow there is a little village called Samvet, and you don't need special permission to go there.
But why would he be going to Samvet? He's probably going to visit one of the Jewish families there, but how many Jewish families are there in Samvet? Only two - the Bernsteins and the Steinbergs. The Bernsteins are a terrible family, so he must be visiting the Steinbergs.
But why is he going? The Steinbergs have only girls, so maybe he's their son-in-law. But if he is, then which daughter did he marry?
Sarah married that nice lawyer from Budapest and Esther married a businessman from Zhadomir, so it must be Sarah's husband. Which means that his name is Alexander Cohen, if I'm not mistaken. But if he comes from Budapest, with all the anti-Semitism they have there, he must have changed his name. What's the Hungarian equivalent of Cohen? Kovacs. But if he changed his name he must have some special status.
What could it be? A doctorate from the University.

At this point Avraham turns to the young man and said, "How do you do, Dr Kovacs?"
"Very well, thank you, sir" answered the startled passenger. "But how is it that you know my name?"
"Oh," replied Avraham, "it was obvious".