Godfather of the Jerome Gambit? (Part III)

Referred to by some as the "Immortal Draw," Hamppe - Meitner, Vienna 1872 can still amuse and delight chess players today.
Here's a modern, improved example.

Wind,Maurits - Winckelmann,Thomas
correspondence, 1993

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


See "Godfather of the Jerome Gambit? (Part I)"

4.Kxf2 Qh4+ 5.Ke3 Qf4+ 6.Kd3 d5 7.Kc3 Qxe4 8.Kb3 Na6


For 8...Nc6 and Steinitz see "Godfather of the Jerome Gambit? (Part II)"

9.a3 Qxa4+ 10.Kxa4 Nc5+ 11.Kb5


"Correct is 11.Kb5!, a move I suggested in Deutsche Schachzeitung 1972, without, however, myself realising its potential" wrote Wolfgang Heidenfeld in Draw! (1982)

Hamppe - Meitner continued instead with 11.Kb4, with the eventual draw, as did a "friendly skirmish" between Alexander Winster and Susan Eira played in London in 1953: 11...a5+ 12.Kb5 Bd7+ 13.Kxc5 b6+?? ( 13...Ne7 14.Nf3 b6 mate) 14.Kxd5 Nf6+ 15.Kxe5 0-0-0 16.d4 Rhe8+ 17.Kf4 Re4+ 18.Kf3? Bg4+ 19.Kf2 Bxd1 20.Bg5 Bxc2 21.Bxf6 gxf6 22.Re1 Rdxd4 23.Ba6+ Kd7 24.Nf3 Rxe1 25.Nxd4? Rxh1 26.Nxc2 Rxh2 27.Bb5+ c6 28.Bc4 Ke7 29.Nd4 c5 30.Nb5 1/2-1/2

11...a5

11...Ne7 is better. Wrote Heidenfeld

This is a suggestion by another German amateur, Johannes Schmedes, so as to avoid the freeing manoeuvre, b4. In most cases this would lead back to – and thus revalidate – the game continuation, but there is one exception: 12.c4! (just as White frees square b4 for the return of the K... so he tries to free square c4... If then 12...d4 13.Kxc5! a5 14.Qa4+ Kd8 15.Qxa5! Rxa5+ 16.Kb4 and White wins.

12.b4

It is only this move, found by the German amateur Josef Ettner, that justifies 11.Kb5. Its point lies in the fact that the b-pawn attacks two black units so that White is assured of freeing square b4 for the return of his K to civilized regions.– Heidenfeld

Taking the Knight, instead, leads to the standard draw: 12.Kxc5 Ne7 13.Bb5+ Kd8 14.Bc6 b6+ 15.Kb5 Nxc6 16.Kxc6 Bb7+ 17.Kb5 Ba6+ 18.Kc6 Bb7+ Ax Rombaldoni - A Bove, U20 Fiuggi, Italy.

12...Ne7 13.bxa5 Nc6 14.Kxc5 Rxa5+ 15.Bb5 Be6 16.c4 d4 17.Nf3 f6 18.Nxd4 1-0