Thanks Stefan! A kind soul here on chesspub already provided me with a copy of the MOB 19 article. It will be interesting to see what Maurits' current views on the matter are. 

[quote]1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!?

This is my current pet line in the Owen defence! Is it playable?! Yes, it is! [/quote]

Interesting stuff. I'm wondering about 4 c3 e5 5 Nf3 though. You mention 5 ...d6 without analysis, following perhaps a game by Lawrence Day? I'm sure this is playable, but Day's approach might not be for everyone ... As another possibility, how about 5 ...ed 6 cd Nb4 7 0-0 Nd3 8 Qd3 Ne7? I wondered too about 4 Nf3. So little stable theory on these lines! Maybe 4 ...Nb4 5 Bc4 e6? -- what do you reckon?

I'm also unsure about the status of the main line you mention with 3 ...Nf6 4 Nd2 and 7 a3. Black has tried various defences/move orders here but on a quick look I'm tempted to think the soundest might be 7 ... d5 8 e5 Nfd7 9 0-0 a5, e.g. 10 Re1 c4 11 Bc2 b5 12 Nf1 h6 as in Narciso Dublan--Lputian, Linares 1996. Black's plan looks quick, direct and aggressive -- is there anything really wrong with this such as would render 3 ...Nc6!? a safer bet?

There is a similar line in the English Defence:

1.d4 e6 2.c4 b6 3.e4 Bb7 4.Bd3 Nc6 5.d5 Nb4 6.Nc3 Nd3 7.Qd3 += (according to an article in New in Chess Yearbook)

Why not try the same here and play d5 followed by c4?

1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!?

This is my current pet line in the Owen defence! Is it playable?! Yes, it is! I spent more than a month in analyzing the arising positions after 1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!? with the help of some of the strongest chess engines! My conclusion is that after Black’s  3…Nc6!? White could hardly get more from the opening than in the line 1. e4 b6 2. d4 Bb7 3. Bd3 Nf6!? 4.Qe2 Nc6! 5.c3 e5 etc. which is played as Black by many GMs: GM E. Bakro, GM A. Ivanov, GM C. Bauer, GM P. Blatny, GM V. Kunin. So, the line 1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!? should be playable for Black! Further, there is an advantage of playing 3…Nc6!? instead of 3…Nf6!? In the later case, e.g. 1. e4 b6 2. d4 Bb7 3. Bd3 Nf6!? after 4.Nd2! {instead of 4.Qe2} it’s very likely for Black to be tricked into a bored and slightly worsened version of the French defence, e.g. 4…e6 5.Nf3 c5 6.c3 Nc6 7.a3 d5 8.e5 etc. So, lets White be tricked a move earlier with that 3…Nc6!? Finally, don’t look at your chess databases: there are no good sample games starting out 1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!? and the matters are much more complex …   
       
Below is listed one of my recent  blitz games using the considered line. 

4. c3! e5! 5. d5! 

{5.Ne2!? d5! or 5.Nf3!? d6 is playable for Black too!}

5…Nce7 6. Ne2 

{After 6.Nf3 Ng6 etc. the arising positions are very similar to the 3…Nf6!? line! Just one example: 1. e4 b6 2. d4 Bb7 3. Bd3 Nf6!? 4. Qe2 Nc6! 5. c3 e5 6. d5 Ne7 7. Nf3 Ng6 8. g3 c6! 9. c4 Bc5 10. Nbd2 a5 11. Nf1 O-O 12. Ne3 b5! …(23) 0-1 A. Bennett (2309) – A. Ivanov (2630), New Hampshire Open 50th, 2000. Another try for White is 6.Nh3!? Ng6 7. O-O Nf6 8. Be3 h5!? 9. f3 h4! 10. Qd2 Nh5 11. b4 a5! 12. f4?! exf4 13. Nxf4 Ngxf4 14. Bxf4 axb4 15. cxb4 Nxf4 16. Qxf4 Qf6=+ …(31) 0-1, N. Povah – J. Speelman (2370), BCF Ch/Morecambe, 1975} 

6…c6!

{An absolutely key move in this type of pawn structure.}

7. c4 Ng6 8. O-O h5!

{Black’s second key (pawn) move aiming for a quick h5-h4-h3! push.}

9. f4?! 

{A dubious move which could be seen up to the master level! Better was 9.Nc3 followed by Be3, f3 etc.}

9…exf4 10. Nxf4 Ne5! 

{What a knight! Black’s dark-squared play begins!}

11. Nc3  Nf6 12. b3!? Bd6!? 

{12... Bc5+!? 13. Kh1 Nfg4 14. Nh3 Bd4! might be even stronger! }

13. Bc2 Qc7! 14. Qd2 h4! 15. Bb2 

{Or 15. h3!? O-O-O 16. a4 a5 17. Bb2 g5!? 18. Nd3 Nh5 19. Ne2 Nxd3 20. Qxd3 f6 21. Rad1 g4! and Black has all the chances to win the game on the kingside!} 

15... h3! 16. g3 Nfg4 17. Nce2 O-O-O 18. Nd4 g6 19. Nf3 Rhe8?! 

{Stronger was 19... Rde8! 20. Nxe5 Nxe5 21. a4 f5!? 22. exf5 g5! 23. dxc6! gxf4! 24. cxb7+ Qxb7 25. Qd5 Ng4!! 26. Qxb7+ Kxb7 and now the ‘obvious’ 27. Bxh8? leads to mate after 27…Bc5+! 28. Kh1 Re2!! etc. } 

20. Rae1 f5!? 21. Nxe5 Nxe5 22. exf5 g5! 23. Nd3? 

{White is aiming for simplifications: logical but … insufficient!} 

23…Nxd3 24. Qxd3 Bc5+! 

{This check was in the air for a long time but now it’s decisive!}

25. Kh1 cxd5 26. cxd5 Qd6! 27. Rd1 Re3! 28. Qd2 Rde8!

{White has a big light-squared problem along the long h1-a8 diagonal + some other big  problems over the first/second rank! The game is over!}

29. Rf2 Bb4 30. Qd4 Re1+! 31. Rf1 Bxd5+! 32. Qxd5 Qxd5+ 33. Be4 Qxe4+ 34. Kg1 Qg2# 0-1


P.S. I think the line 1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!? is more or less underestimated and it may suit some players with an open-minded approach to the chess. The arising positions after 1. e4 b6 2. d4 Bb7 3. Bd3 Nc6!? 4.c3 e5 5.d5 Ne7 etc. are much more complex and interesting than those arising after 3…e6 {the main line!?} 4.Nf3 c5 5.c3! Nf6 6.Nbd2 Nc6 7.a3! d5 8.e5 etc. or 1. e4 b6 2. d4 Bb7 3. Bd3 Nf6!? 4.Nd2! e6 5.Nf3 c5 6.c3 Nc6 7.a3 d5 8.e5 etc.