What follows is my discovery/study of an offbeat but seemingly very strong move in a gambit opening. It is also a sort of study of opening variations and how they develop, and a look at how a sequence of moves can work tactically because of a common strategic theme (in this case exploiting black's queen).
This came from a Blackmar-Diemer Gambit, and it is white's move.
Here is what led to the position:
1.e4 d5 2.d4 {transposing to the BDG} dxe4 3.Nc3 e5 {About 6 months ago, this was rather a rare bird in my games. Now, I meet it about 7 or 8 times out of 10. I'd be willing to bet there is a new book or article advocating it for black.} 4.Qh5 {Sneiders Attack ... Rec'd by Ken Smith} Qxd4 {Also rare ... I usually get exd4 Bc4.} 5.Be3 {The a1 rook would like to play.} Qb4 {My next move seems to leave theory. The "book" reply is 6.Qxe5+ and if Qe7 7.Qxe4 retains material equality with a slight lead in development ... 7.Qf4 plays for more. e4 is still under attack and Nd5 is also a threat.} 6.0-0-0 {Natural} Nc6 {holds e5} 7.Nd5 {One idea was possibly 7. ... Qd6 8.Bc5} Qa5 {Here theres is an old trick from other BDG lines, but it doesn't quite work. I studied 8.Bb6, to remove the guard of c7. After Bb6 cxb6 (or axb6) 9.Nc7+ Ke7, I saw no follow up to my attack. This Bb6 to get to c7 trick is a nice one to know.}8.Bb5 {back to attacking e5} Bd6 {It appears as though all of my fork tricks and attacks on e5 are gone. I began to feel bad about my position here. I played an inferior move and got lucky later in the game. There is one nice move here that keeps white's attack going and gives white a slight pull!} 9.a4 {! - not played in the game- This is really something. White doesn't continue developing pieces AND weakens his castled position. You don't see a move like this often in a gambit opening. I will demonstrate some ideas in the next few pgns.}
Variation 1 : 9.a4! a6 Edit: 1A
1.e4 d5 2.d4 dxe4 3.Nc3 e5 4.Qh5 Qxd4 5.Be3 Qb4 6.0-0-0 Nc6 7.Nd5 Qa5 8.Bb5 Bd6 9.a4 a6 {walks right into the idea} 10.b4 {The queen is almost trapped.} Bxb4 {e5's defense is deflected.} 11.Qxe5+ Kf8 {Be6 is better, but white is still winning.} 12.Nxb4 Qxb4 13.Rd8+ Nxd8 14.Qe8 {With shades of the opera game}
Edit: 1B
1.e4 d5 2.d4 dxe4 3.Nc3 e5 4.Qh5 Qxd4 5.Be3 Qb4 6.0-0-0 Nc6 7.Nd5 Qa5 8.Bb5 Bd6 9.a4 a6 10.b4 Bxb4 11.Qxe5+ Kf8 12.Nxb4 Nxe5 13.Bc5+ {another nice mate} Ne7 14.Rd8
Variation 2 : 9.a4! Nf6
1.e4 d5 2.d4 dxe4 3.Nc3 e5 4.Qh5 Qxd4 5.Be3 Qb4 6.0-0-0 Nc6 7.Nd5 Qa5 8.Bb5 Bd6 9.a4 Nf6 {developing} 10.Qg5 {attacks g7 and f6} Nxd5 {not best but natural} 11.Qxg7 {a logical line follows} Rf8 12.Rxd5 Qe1+ 13.Rd1 {Ideas of Rxd6 and Bh6 begin to appear} Qb4 14.c3 Qb3 15.Rxd6 cxd6 16.Bh6 {White is winning.}
Variation 3 : 9.a4! Kf8
1.e4 d5 2.d4 dxe4 3.Nc3 e5 4.Qh5 Qxd4 5.Be3 Qb4 6.0-0-0 Nc6 7.Nd5 Qa5 8.Bb5 Bd6 9.a4 Kf8 {Maybe Best ... But hard to find} 10.Bd2 {again exploiting the trapped queen theme} Nb4 11.Bxb4 Bxb4 12.c3 {If the bishop moves, 13.b4 wins the trapped queen!} c6 {queen luft} 13.cxb4 Qd8 14.Ne3 {White retains the piece.}
These variations show what a tricky move 9.a4 is. It's such an odd move that I still don't half believe how well it seems to work.
Imagine if someone took all the openings and came up with fresh approaches like this!