Many Roads Lead to Fischer - Reshevsky (game 5)

Continuing with Fischer - Reshevsky, Match 1961 (Game 5), the game started 1.d4 Nf6 2.c4 e6 3.Nc3 d5 4.cxd5 Nxd5 5.Nf3 c5 6.e3 Nc6 7.Bd3 Be7 8.O-O O-O 9.a3 cxd4 10.exd4 Nf6, reaching the position shown in the diagram.

1961 Match (game 5)
Fischer, Robert

Reshevsky, Samuel
(After 10...Nd5-f6)
[FEN "r1bq1rk1/pp2bppp/2n1pn2/8/3P4/P1NB1N2/1P3PPP/R1BQ1RK1 w - - 0 11"]

When I researched this opening, I was surprised to find that most games reaching the diagrammed position started 1.e4 instead of 1.d4. A little more research showed why.

Of the ~150 games I found, about two-thirds started 1.e4, and two-thirds of those continued 1...c5. Now the most common move was 2.c3 (two-thirds again), followed by 2...d5 3.exd5 Qxd5 4.d4 e6 5.Nf3. Now there are many transpositions to arrive at the diagram, but the most common continuation was 5...Nf6 6.Bd3 Nc6 7.O-O cxd4 8.cxd4 Be7 9.Nc3 Qd8 10.a3 O-O. In this line, instead of using two tempi on ...Nxd5 & ...Nf6, as in the Fischer - Reshevsky game, Black uses them on ...Qxd5 & ...Qd8.

The players can vary at several points, but the roads eventually offer a return to Fischer - Reshevsky. For example, many games continued 2.Nf3, when White played c2-c3 later. Also possible is 2.d4 cxd4 3.c3 d5 4.exd5 Qxd5 5.cxd4.

Most of the other 1.e4 games that were not Sicilians, were Caro-Kanns. For example, 1...c6 2.d4 d5 3.exd5 cxd5 4.c4 Nf6 5.Nc3 e6 6.Nf3 Be7 7.cxd5 Nxd5 8.Bd3 Nc6 9.O-O O-O 10.a3 Nf6. Another path after 1...c6 is 2.c4 d5 3.exd5 (3.cxd5 cxd5 4.exd5 is the same) 3...cxd5 4.cxd5 Qxd5 5.Nc3 Qd8 6.d4, and it's easy to see that the game can follow the same direction as before.

Two other paths after 1.e4 are 1...d5 2.exd5 Nf6 3.c4 c6 4.d4 cxd5, and 1...e6 2.d4 c5 3.c3 d5 4.exd5 Qxd5. The diagrammed position can arise after different moves leading to closed games -- 1.c4 (1...c6 2.e4), 1.d4 (as in Fischer - Reshevsky), and 1.Nf3 -- all known transpositions that lead to other positions as well.