user11144: [FEN ""]

1.e4 e5 2.Nc3 Bc5 3.Na4 Bxf2+

For those of you who never heard of Hamppe-Meitner. Now I dimly remember that a super engine somewhere found a White win, but even the bringer of the news ceded that a super-duper engine could reverse that. (See e.g. here for the complete game and how they still discuss...)
Can you link me to a human-annotated (a mere list with cryptical "+0.5 after Kj9" is quite useless, see below) computer analysis, also with evaluations of the side variants? Mustn't be each and any move, but at least the sensible ones, if one can talk of sensible in that crazy positions...)
The greater plan is to turn it into a Euwe-style "I test myself" test for the chess kids I train, to boost their imagination. Of course I must deliver when I get asked why Kj9 botches the draw!

user32005: You might want to go with http://www.kenilworthchessclub.org/games/java/2009/hamppe-meitner.htm however no guarantees on its being up to date.

user10380: Using Stockfish 14 at depth up to 25 I find:
4 Kxf2 (Ke2? Bxg1! 5 Rxg1 d5 {-6.3}) Qh4+
5 Ke3 (g3 Qxe4! 6 Qe1/Qe2 Qxh1 7 Qxe5+ Kf8
  (Ne7? 8 Nf3! {+1.3}) 8 Bg2/Qxc7 {-0.2}) Qf4+
6 Kd3 d5
7 Qe1 (Kc3 d4+ 8 Kb3 Qxe4 {-0.9} (Be6+? 9 c4! {+0.4})) Nf6
8 g3 dxe4+ (Qg4 9 c3 {+0.1})
9 Kc3 Nd5+ 10 Kb3 Qf6 11 c4 b5 (Nc6)
12 cxb5 (cxd5? bxa4+! {-0.9}) Nd7 {-0.7}

[fen "rnbqk1nr/pppp1ppp/8/4p3/N3P3/8/PPPP1bPP/R1BQKBNR w - - 0 4"]

4. Kxf2 (4. Ke2? Bxg1! 5. Rxg1 d5 {-6.3}) Qh4+ 5. Ke3 (5. g3 Qxe4! 6. Qe1 (6. Qe2 Qxh1) Qxh1 7. Qxe5+ Kf8 (7...Ne7? 8. Nf3! {+1.3}) 8. Bg2 (8. Qxc7) {-0.2}) Qf4+ 6. Kd3 d5 7. Qe1 (7. Kc3 d4+ 8. Kb3 Qxe4 {-0.9} (8...Be6+? 9. c4! {+0.4})) Nf6 8. g3 dxe4+ (8...Qg4 9. c3 {+0.1}) 9. Kc3 Nd5+ 10. Kb3 Qf6 11. c4 b5 (11...Nc6) 12. cxb5 (12. cxd5? bxa4+! {-0.9}) Nd7 {-0.7}

Figures are evaluations in terms of advantage to White in pawns. These are rough --- different evaluations might give slightly different figures.
If there is a line by which White can guarantee a winning position, Stockfish can't find it at that depth. I get the impression that Stockfish reckons that Black has a slight advantage.
365chess.com's openings-database rates 3 Na4 Bxf2+ at -1.00, and says that it is very rare: only 28 3 Na4 games of which 24 are 3 Na4 Bxf2+, compared to 551 for 3 Bc4. Game totals are of games in its big database.

11144: <pre><code>[FEN &quot;&quot;]

1.e4 e5 2.Nc3 Bc5 3.Na4 Bxf2+
</code></pre>
<p>For those of you who never heard of Hamppe-Meitner. Now I dimly remember that a super engine somewhere found a White win, but even the bringer of the news ceded that a super-duper engine could reverse that. (See e.g. <a href="https://www.chessgames.com/perl/chessgame?gid=1250160" rel="nofollow noreferrer">here</a> for the complete game and how they still discuss...)</p>
<p>Can you link me to a human-annotated (a mere list with cryptical &quot;+0.5 after Kj9&quot; is quite useless, see below) computer analysis, also <em>with</em> evaluations of the side variants? Mustn't be each and any move, but at least the sensible ones, if one can talk of sensible in that crazy positions...)</p>
<p>The greater plan is to turn it into a Euwe-style &quot;I test myself&quot; test for the chess kids I train, to boost their imagination. Of course I must deliver when I get asked why Kj9 botches the draw!</p>
 32005: <p>You might want to go with <a href="http://www.kenilworthchessclub.org/games/java/2009/hamppe-meitner.htm" rel="nofollow noreferrer">http://www.kenilworthchessclub.org/games/java/2009/hamppe-meitner.htm</a> however no guarantees on its being up to date.</p>
 10380: <p>Using Stockfish 14 at depth up to 25 I find:</p>
<pre><code>4 Kxf2 (Ke2? Bxg1! 5 Rxg1 d5 {-6.3}) Qh4+
5 Ke3 (g3 Qxe4! 6 Qe1/Qe2 Qxh1 7 Qxe5+ Kf8
  (Ne7? 8 Nf3! {+1.3}) 8 Bg2/Qxc7 {-0.2}) Qf4+
6 Kd3 d5
7 Qe1 (Kc3 d4+ 8 Kb3 Qxe4 {-0.9} (Be6+? 9 c4! {+0.4})) Nf6
8 g3 dxe4+ (Qg4 9 c3 {+0.1})
9 Kc3 Nd5+ 10 Kb3 Qf6 11 c4 b5 (Nc6)
12 cxb5 (cxd5? bxa4+! {-0.9}) Nd7 {-0.7}
</code></pre>
<pre><code>[fen &quot;rnbqk1nr/pppp1ppp/8/4p3/N3P3/8/PPPP1bPP/R1BQKBNR w - - 0 4&quot;]

4. Kxf2 (4. Ke2? Bxg1! 5. Rxg1 d5 {-6.3}) Qh4+ 5. Ke3 (5. g3 Qxe4! 6. Qe1 (6. Qe2 Qxh1) Qxh1 7. Qxe5+ Kf8 (7...Ne7? 8. Nf3! {+1.3}) 8. Bg2 (8. Qxc7) {-0.2}) Qf4+ 6. Kd3 d5 7. Qe1 (7. Kc3 d4+ 8. Kb3 Qxe4 {-0.9} (8...Be6+? 9. c4! {+0.4})) Nf6 8. g3 dxe4+ (8...Qg4 9. c3 {+0.1}) 9. Kc3 Nd5+ 10. Kb3 Qf6 11. c4 b5 (11...Nc6) 12. cxb5 (12. cxd5? bxa4+! {-0.9}) Nd7 {-0.7}
</code></pre>
<p>Figures are evaluations in terms of advantage to White in pawns. These are rough --- different evaluations might give slightly different figures.</p>
<p>If there is a line by which White can guarantee a winning position, Stockfish can't find it at that depth. I get the impression that Stockfish reckons that Black has a slight advantage.</p>
<p><a href="https://www.365chess.com/opening.php?m=5&amp;n=448&amp;ms=e4.e5.Nc3.Bc5&amp;ns=3.5.55.448" rel="nofollow noreferrer">365chess.com</a>'s openings-database rates 3 Na4 Bxf2+ at -1.00, and says that it is very rare: only 28 3 Na4 games of which 24 are 3 Na4 Bxf2+, compared to 551 for 3 Bc4. Game totals are of games in its big database.</p>
