This position might seem familiar to the attentive reader as this position can be reached in the EUwe defense after 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 e6 6.Bg5 Be7 7.Bd3 Nbd7 8.0-0 0-0 9.Qe1 c6 10.Qh4 h6. The only difference is that it is white to move in the Euwe, whilst it is black's turn in the Euwe-O'Kelly. Talking about a small difference.
But even with white one move down, it seems that 11.Bd3 is winning !!
a/ 11...hxg5 12.Nxg5 (++)
b/ 11...Nb6 12.Bxh6 (++)
c/ 11...Nd5 12.Nxd5 Bxg5 13.Nxg5 Qxg5 14.Qxg5 hxg5 15.Ne7+ Kh8 16.Rae1 (+=)
d/ 11...Qa5 12.Ne4
...d1/ 12...Re8 13.Rae1 (+)
...d2/ 12...Rd8 13.c3 (+)
...d3/ 12...Bd8 13.b4 (+)
...d4/ 12...hxg6 13.Nexg5 (++)
e/ 11...Qb6 12.Bxh6 (++)
f/ 11...Qc7 12.Bxh6 (++)
g/ 11...c5 12.Bxh6 (++)
Let's consider balck's best reply in more detail : 11...Re8 12.Bxh6 (diagram)
Declining the piece is no option for black :
...h1/ 12...Nf8 13.Ne5 (++)
...h2/ 12...Nd5 13.Nh7+ (++)
...h3/ 12...Qa5 13.Bg5 (++)
And now the killer move 12...gxh6 13.Ne5 !! Analysis shows only 13...Bf8 offers some chances. But now white brings in an extra piece with 14.Rf3 (diagram)
Again, black has only one move 14...Bg7, followed by the logical 15.Rg3 (diagram)
As "Anonymous" pointed out, black has to give back the piece with 15...Ne4, but white stays on top after 16.Qxe4 f5 17.Qe3 Nxe5 18.Qxe5 (+=)
Apparently, the Euwe defense is so strong that it evens wins with the move down !
Thank you "Anonymous" for this great line !
e/ 11...Qb6 12.Bxh6 (++)
f/ 11...Qc7 12.Bxh6 (++)
g/ 11...c5 12.Bxh6 (++)
Let's consider balck's best reply in more detail : 11...Re8 12.Bxh6 (diagram)
Declining the piece is no option for black :
...h1/ 12...Nf8 13.Ne5 (++)
...h2/ 12...Nd5 13.Nh7+ (++)
...h3/ 12...Qa5 13.Bg5 (++)
And now the killer move 12...gxh6 13.Ne5 !! Analysis shows only 13...Bf8 offers some chances. But now white brings in an extra piece with 14.Rf3 (diagram)
Again, black has only one move 14...Bg7, followed by the logical 15.Rg3 (diagram)
As "Anonymous" pointed out, black has to give back the piece with 15...Ne4, but white stays on top after 16.Qxe4 f5 17.Qe3 Nxe5 18.Qxe5 (+=)
Apparently, the Euwe defense is so strong that it evens wins with the move down !
Thank you "Anonymous" for this great line !