(B23) Korchnoi
1. e4 c5 2. Nc3 e6 3. g3 d5
(B23) Camaleón
1. e4 c5 2. Nc3 Nc6 3. Nge2
(B23) Zukertort
1. e4 c5 2. Nc3 Nc6 3. f4
(B23) Schofman
1. e4 c5 2. Nc3 Nc6 3. f4 g6 4. Nf3 Bg7 5. Bc4 e6 6. f5