These moves were studied by the earliest chess masters. Some of our examples are from Howard Staunton's Chess Player's Handbook, written in the 19th century. The same lines have been investigated by subsequent generations of chess players, including the great Estonian grandmaster Paul Keres. With moves like 2...d5 and 2...f5, there is still considerable debate about best play, 150 years after Staunton.
If you think one of these moves suits your style, don't let us discourage you; give it a try. Whether you decide to play it in competition or not, you will learn a lot about tactics by studying it.
