user2299: Has this gambit (6.Ng5!) been played? (I only found games with 6.Ne5.) Is it any good? Is it the refutation of Black's silly 3...h5 (the Wagenbach Defense)?
[FEN ""]

1.e4 e5 2.f4 exf4 3.Nf3 h5 4.d4 g5 5.h4 g4 6.Ng5 f6 7.Bxf4 fxg5 8.Bxg5 Be7 9.Qd2


user12873: From my analysis, the line you give appears to be the best way White can play. After 9.Qd2, Stockfish 10 at depth 28 gives roughly +1. So I think it qualifies as a refutation of 3...h5.
I couldn't find any games where 6.Ng5 was played, but I did find a game that reached the same position on move 6 via transposition. The game was from 1788 (!) in the "London Casual Games" between two players named Cotter and Von Bruehl:
[White "Cotter"]
[Black "Von Bruehl"]
[Event "London Casual Games"]
[Date "1788"]

[fen ""]

1.e4 e5 2.f4 exf4 3.Nf3 g5 4.h4 g4 5.Ng5 h5 6.d4 {Transposing to the diagram you gave} f6 7.Bxf4 fxg5 8.hxg5 (8.Bxg5 {Is stronger, following your line}) d5 9.e5 Bf5 10.Bd3 Ne7 11.O-O Bg7 12.Bg3 Rf8 13.Bh4 Qd7 14.Nc3 a6 15.Qe2 Nbc6 16.Bf2 O-O-O 17.Na4 Bxd3 18.Qxd3 Nxe5 19.Qb3 b5 20.dxe5 bxa4 21.Qc3 d4 22.Qd3 Qb5 23.Qa3 Ng6 24.b3 Bxe5 25.bxa4 Qc6 26.Rab1 0-1.


2299: <p>Has this gambit (6.Ng5!) been played? (I only found games with 6.Ne5.) Is it any good? Is it the refutation of Black's silly 3...h5 (the <a href="https://en.wikipedia.org/wiki/King%27s_Gambit#Wagenbach_Defense:_3...h5" rel="nofollow noreferrer">Wagenbach Defense</a>)?</p>

<pre><code>[FEN ""]

1.e4 e5 2.f4 exf4 3.Nf3 h5 4.d4 g5 5.h4 g4 6.Ng5 f6 7.Bxf4 fxg5 8.Bxg5 Be7 9.Qd2
</code></pre>
 12873: <p>From my analysis, the line you give appears to be the best way White can play. After 9.Qd2, Stockfish 10 at depth 28 gives roughly +1. So I think it qualifies as a refutation of 3...h5.</p>

<p>I couldn't find any games where 6.Ng5 was played, but I did find a game that reached the same position on move 6 via transposition. The game was from 1788 (!) in the "London Casual Games" between two players named Cotter and Von Bruehl:</p>

<pre><code>[White "Cotter"]
[Black "Von Bruehl"]
[Event "London Casual Games"]
[Date "1788"]

[fen ""]

1.e4 e5 2.f4 exf4 3.Nf3 g5 4.h4 g4 5.Ng5 h5 6.d4 {Transposing to the diagram you gave} f6 7.Bxf4 fxg5 8.hxg5 (8.Bxg5 {Is stronger, following your line}) d5 9.e5 Bf5 10.Bd3 Ne7 11.O-O Bg7 12.Bg3 Rf8 13.Bh4 Qd7 14.Nc3 a6 15.Qe2 Nbc6 16.Bf2 O-O-O 17.Na4 Bxd3 18.Qxd3 Nxe5 19.Qb3 b5 20.dxe5 bxa4 21.Qc3 d4 22.Qd3 Qb5 23.Qa3 Ng6 24.b3 Bxe5 25.bxa4 Qc6 26.Rab1 0-1.
</code></pre>
