This King's Gambit Accepted (1.e4 e5 2.f4 exf4) theme tournament was organized by Georg Marco and took place in Abbazia on the Adriatic coast, then part of Austria-Hungary, known today as Opatija in Croatia. The venue was the Casino des Étrangers, a fitting location for the King's Gambit.
Of the 12 players, who met each other twice, only Spielmann, Duras, Cohn and Leonhardt were regarded as masters at the time. This may be one of the reasons why no tournament book appeared, and many of the games are apparently lost forever.
Aurbach forfeited his Round 7 game against Flamberg, upset after he lost his Round 6 game against Rosselli on time in a winning position, and withdrew from the second cycle for medical reasons. So only 120 games were played. 77 games are available here, including a few incomplete ones, 43 games are lost.
The tournament was a big success for Rudolf Spielmann, but a tragedy for the King's Gambit. White scored only +40 -59 =21, even worse than in Vienna (1903) (+32 -37 =20). It's not just the "modern" systems of defence (with an early ...d5) that caused white trouble. From the games available, white scored +4 -6 =2 against the Abbazia Defence (3.Nf3 d5 4.exd5 Nf6) and +4 -9 against 3.Bc4 d5, but the Hanstein, Philidor and Muzio did just as badly.
For Spielmann's funeral oration a decade later, see Game Collection: Vom Krankenlager des Königsgambits.
Abbazia, Austria-Hungary (Croatia), 15 January - 12 February 1912
01 02 03 04 05 06 07 08 09 10 11 12 Pts
1 Spielmann ** ½0 1½ 11 11 11 10 10 1½ 10 1½ 1- 15
2 Duras ½1 ** 10 10 ½1 01 01 01 01 11 ½1 1- 13½
=3 Cohn 0½ 01 ** 00 01 01 11 ½½ 11 01 11 0- 11½
=3 Reti 00 01 11 ** 10 10 1½ 10 1½ 10 ½1 0- 11½
5 Lowcki 00 ½0 10 01 ** 11 00 11 ½1 01 11 0- 11
=6 Flamberg 00 10 10 01 00 ** 00 1½ 1½ 11 1½ 1- 10½
=6 Freymann 01 10 00 0½ 11 11 ** 00 10 0½ ½1 1- 10½
8 Szekely 01 10 ½½ 01 00 0½ 11 ** 0½ 01 01 0- 9
9 Leonhardt 0½ 10 00 0½ ½0 0½ 01 1½ ** 01 ½½ ½- 8
=10 Nyholm 01 00 10 01 10 00 1½ 10 10 ** 00 0- 7½
=10 Rosselli 0½ ½0 00 ½0 00 0½ d0 10 ½½ 11 ** 1- 7½
12 Aurbach 0- 0- 1- 1- 1- 0- 0- 1- ½- 1- 0- ** 5½
The missing games:
(Round 5) Flamberg vs Von Freymann (3.Nf3 g5 4.Bc4 g4 5.O-O) 0-1, 21 moves; Duras vs Lowcki (3.Bc4) draw
(Round 7) Rosselli vs Duras (3.Nf3) draw; Flamberg vs Aurbach (forfeit) 1-0; Leonhardt vs Von Freymann 0-1; Szekely vs Lowcki (3.Nf3) 0-1
(Round 8) Szekely vs Rosselli (3.Nf3) 0-1
(Round 9) Leonhardt vs Aurbach (3.Nf3) draw; Rosselli vs Lowcki (3.Nf3 g5 4.Bc4 g4 5.O-O) 0-1
(Round 10) Cohn vs Reti (3.Nf3) 0-1; Aurbach vs Nyholm (3.Nf3) 1-0
(Round 11) Flamberg vs Lowcki (3.Nf3 g5 4.h4 g4 5.Ne5) 0-1
(Round 12) Lowcki vs Cohn (3.Nf3 g5 4.Bc4 Bg7 5.h4) 0-1
(Round 13) Flamberg vs Leonhardt (3.Nf3 g5 4.Bc4 g4 5.O-O) draw; Rosselli vs Nyholm (3.Nf3 Nf6 4.Nc3 Nc6 5.d4 d5 6.exd5 Nxd5 7.Nxd5 Qxd5 8.Bxf4 Bd6 9.Bxd6 Qxd6 10.c3 Bg4 11.Bc4 O-O-O 12.O-O f6 13.Qa4) 1-0
(Round 14) Cohn vs Duras (3.Bc4) 1-0; Reti vs Rosselli (3.Nf3 g5 4.Bc4 Bg7 5.h4) 1-0; Nyholm vs Flamberg (3.Bc4) 0-1; Leonhardt vs Spielmann (3.Bc4) draw
(Round 15) Rosselli vs Von Freymann (3.Bc4) 0-1; Szekely vs Cohn (3.Pf3 g5 4.Bc4 Bg7 5.h4) draw
(Round 16) Nyholm vs Leonhardt (3.Bc4) 0-1; Reti vs Spielmann 0-1; Lowcki vs Duras (3.Nf3 g5 4.Bc4 Bg7 5.h4) 0-1
(Round 17) Leonhardt vs Reti (3.Nf3) draw; Spielmann vs Von Freymann (3.Bc4) 0-1; Flamberg vs Cohn (3.Bc4) 0-1; Szekely vs Duras (3.Nf3) 0-1
(Round 18) Cohn vs Spielmann (3.Bc4) draw
(Round 19) Nyholm vs Von Freymann (3.Bc4) draw; Leonhardt vs Cohn (3.Nf3 g5 4.h4 g4 5.Ne5) 0-1; Reti vs Lowcki (3.Nf3) 0-1
(Round 20) Szekely vs Flamberg (3.Nf3 g5 4.Bc4 g4 5.O-O) draw; Cohn vs Nyholm (3.Bc4) 1-0; Von Freymann vs Reti (3.Nf3) draw; Lowcki vs Rosselli (3.Nf3 g5 4.h4 g4 5.Ne5) 1-0
(Round 21) Reti vs Cohn (3.Nf3 g5 4.Bc4 Bg7 5.O-O d6 6.d4 h6 7.c3 Ne7 8.g3 g4 9.Nh4 f3 10.Na3 O-O 11.Bf4) 1-0; Flamberg vs Rosselli (3.Bc4) draw; Leonhardt vs Duras (3.Bc4) 0-1
(Round 22) Rosselli vs Spielmann (3.Bc4) draw; Szekely vs Leonhardt (3.Nf3 g5 4.Bc4 g4 5.O-O) draw; Duras vs Nyholm (3.Bc4) 1-0; Cohn vs Von Freymann (3.Bc4) 1-0; Lowcki vs Flamberg (3.Nf3 g5 4.Bc4 Bg7 5.h4) 1-0
Original collection: Game Collection: Abbazia 1912, by User: sneaky pete.