Chess is a scientific game and its literature ought to be placed on the basis of the strictest truthfulness, which is the foundation of all scientific research. — W. Steinitz

C21-C22

**C21**
1.e4 e5 2.d4	Center Game:
2…d5	Center Game: Breyer
2…d6	Center Game: Maróczy
2…d6 3.dxe5 Bd7	Center Game: Maróczy (Philidor)
2…exd4 3.f4	Center Game: Halasz
2…exd4 3.Nf3 c5 4.Bc4 b5	Center Game: Kieseritzky
2…exd4 3.c3	Center Game: Danish
2…exd4 3.c3 Ne7	Center Game: Danish (Svenonius)
2…exd4 3.c3 Qe7 4.cxd4 Qxe4+ 5.Be2 Qxg2 6.Bf3 Qg6	Center Game: Danish (Rosentreter)
2…exd4 3.c3 d5	Center Game: Danish (Sorensen)
2…exd4 3.c3 d5 4.exd5 Nf6 5.cxd4 Bb4+	Center Game: Danish (Schlechter Attack)
2…exd4 3.c3 dxc3 4.Nxc3 Bb4 5.Bc4	Center Game: Danish (Alekhine)
2…exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2 Qe7	Center Game: Danish (Collijn)
2…exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2 d5	Center Game: Danish (Schlechter Defense)

**C22**
1.e4 e5 2.d4 exd4 3.Qxd4	Center Game:
3…Nc6 4.Qc4	Center Game: Hall
3…Nc6 4.Qe3	Center Game: Paulsen
3…Nc6 4.Qe3 f5	Center Game: Paulsen (L'Hermet)
3…Nc6 4.Qe3 Bb4+ 5.c3 Be7	Center Game: Paulsen (Charousek)
3…Nc6 4.Qe3 Nf6	Center Game: Paulsen (Berger)
3…Nc6 4.Qe3 Nf6 5.Nc3 Bb4 6.Bd2 0-0 7.0-0-0 Re8 8.Bc4 d6 9.Nh3	Center Game: Paulsen (Kupreichik)