Indian defences

In chess openings, the Indian defences are characterized by the opening moves 1. d4 Nf6, although they can be reached by other move orders. These defences have a vast body of theory and have been employed by nearly all masters since the early twentieth century. They are all to varying degrees hypermodern defences, where Black invites White to establish an imposing presence in the centre with the plan of drawing it out, undermining it, and destroying it.

The Indian defences are considered more ambitious and double-edged than the symmetrical reply 1 ... d5. In the Queen's Gambit Declined, Black accepts a cramped, passive position with the plan of gradually equalizing and obtaining counterplay. In contrast, breaking symmetry on move one leads to rapid combat in the centre, where Black can obtain counterplay without necessarily equalizing first.

The usual White second move is 2. c4, grabbing a larger share of the centre and allowing Nc3, to prepare e4, without blocking the c-pawn. Black then has three major choices and several more offbeat alternatives:
*2 ... g6, preparing a fianchetto of the king's bishop and entering the King's Indian or Grünfeld Defence.
*2 ... e6, freeing a line for the king's bishop to move out into the centre and leading into the Nimzo-Indian Defence, Bogo-Indian Defence, Queen's Indian, Modern Benoni, or regular lines of the Queen's Gambit Declined.
*2 ... c5, the Modern Benoni, with an immediate counter-punch in the centre.
*2 ... d6, the Old Indian Defence, a sound but unambitious move.
*2 ... b6, the "Accelerated Queen's Indian", which is playable although modern theory favours the Queen's Indian only after 2... e6 3 Nf3.
*2 ... c6, the Slav-Indian Defence, an obscure idea that may transpose into the King's Indian or Slav.
*2 ... e5!?, the Budapest Defence, a lively countergambit. White cannot hold on to his extra pawn without making compromises in the deployment of his pieces, so he often chooses to return the pawn and retain the initiative.