Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

These are both supposed to be Oswald's signature, but they are as different as night and day. The top one was from Japan from a document concerning Oswald's court martial. The bottom one was from Russia- Oswald's letter requesting Soviet citizenship.

They are clearly different handwritings with a completely different stroke, style, and letter formation. But, take a close look at the bottom one. The "s" in Oswald doesn't look anything like an "s". I don't see that as being a cursive s or a printed s. 

But, here's a possibility. If you look closely, his "s" looks like it might have been drawn as a "3". In the Russian alphabet, "3" is their letter for "z". Although his name was spelled "Oswald" it was pronounced "Ozwald". Is it possible that there was some English/Russian fusion going on in his mind by someone who was not a native English speaker?

But regardless, those are definitely different signatures.