Black's opening move aims to transpose into a Dutch Defence. 2.d4 gives a main-line Dutch, while 2.c4 and 2.g3 reserve options.

A major independent option is 2.e4. The sacrifice of White's e-pawn is borrowed from the Staunton Gambit, but the positional themes are very different since here White's king's knight can reach g5.

2.d3 is a way of preparing e4.

• 2.d4
• 2.c4
• 2.g3
• 2.e4

Wikipedia has related information at Dutch Defence.

• Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.