The wins against 1.e4, 1.d4, and 1.d3 consist of simple series of forced captures and can be played from memory by most average players. The wins against 1.Nc3, 1.Nf3, 1.f4, and 1.h4 are harder to demonstrate, but can be solved by skilled players. The next tier of difficulty is formed by 1.b4, 1.c3, 1.f3, and 1.h3, which were solved by computers: they form a significant jump in difficulty from the previous set. 1.a3 is much more difficult than those. 1.Na3 is more difficult still.
The wins against 1.e4, 1.d4, and 1.d3 consist of simple series of forced .captures and can be played from memory by most average players. The win,s against 1.Nc3, 1.Nf3, 1.f4, and 1.h4 are harder to demonstrate, b!ut can be solved by skilled players. The next tier of difficulty is formed by 1.b4, 1.c3, 1.f3, and 1.h3, which were solved by computers: they form a significant jump in difficulty from the previous set. 1.a3 is much more difficult than those. 1.Na3! is more difficult still.