Owen Defense 1.e4 b6

one in the club plays the Owen Defence each time I play e4

he plays b6

I don't understand it but he is doing pretty well with the opening and even won against a fide rated 2000 player.

To me b6 looks a little weak.

How would you play against the Owen Defence?

I've played the opening once or twice when the opponent knows my repertoire inside-out, and as Estragon says, for surprise value more than anything else. Here's an exciting game I played recently:

A quick owen's miniature :

Greco vs. NN

Such an early f5 is probably not prudent.  Building it with e6 (which also frees the king's bishop) is probably better.

You can use the little brown chessboard square icon on the toolbar of the message box to make a diagram.

i play it a lot in blitz and bullet. my dad plays it in OTB

Is 3.Bd3 the best move? Using the "knights first" beginner's principle I might be tempted to play 3.Nc3. You might have to do Bd3 as well if he puts pressure on d4. But, otherwise, might it not be best to keep it in reserve for a more active move (Bc4/5)?

Then again, I like to play c3 so perhaps 3.Nd2 is optimal?!

bd3 are mainline

Bd3 is better because it doesn't allow Bb4 which puts extra pressure on the pawn. Of course Nc3 is not a bad move, just not the best.  
This Nd2 idea is interesting, but why would white play 4. Bb5, what is the point? And of course black doesn't play Bb4 if he can't pin the knight with it attacking the pawn. 

According to Basman's Winning With the St. George Attack (which also discusses the somewhat related 1..b6) the ideal setup for White is with e4 + d4 + Bd3 + c3 + Nf3 + Qe2 + a3 + O-O, leaving the QN on b1 for the time being so as not to block the c1-h6 diagonal.  (And to discourage a Black ..cxd4 because it would give White a good square on c3 for this knight)

The only way to acheive this setup is to play 3.Bd3; any other defense of the e4 pawn would interfere with the plan.  This is why 1...b6 is more plausible against 1.c4 or 1.Nf3 than against 1.d4 or 1.e4.

3...f5 is known to be a forced loss for Black.

3...e6 should be met with 4.Nf3 (so that g2 is not exposed) and ..f5 yet again needs more preparation.  Sometimes this stroke is positionally appealing a bit later but Black must be patient.

I never, never consider any opening as "weak." Every opening has it's own strengths and weaknesses. Each is unique. I just happen to slightly more comfortable playing against some, than others.

I learned a long time ago, never to underestimate any opening. (The hard way.) The minute I do, my opponent will be all over me like white on rice.

About 20 years ago, someone played 1.a3 against me in a USCF Postal match. The game was a hard-fought draw. 1.a3 is useful to shed a tempo and then play something with reversed colors. Playing white with the black pieces and the board as a mirror image (king/queen sides) is a bit confusing. More so over the board than in postal.

Think a correspondence game I played went like this: