The first player to write extensively about the concept of two weaknesses was Nimzowitsch, who had a chapter on “Alternation” in his classic book, My System. By a coincidence of truly Plaskettian proportions, my own new book, “Nimzowitsch Move by Move” (see http://www.amazon.co.uk/Nimzowitsch-Move-Steve-Giddins/dp/178194198X ) has just been published by Everyman, and includes 30 of Nimzo’s best games, deeply annotated in the Q&A style used in the series. That seems a suitably tenuous, but nonetheless sufficient excuse to give a classic example of the man himself employing two-front strategy.
The game that follows is annotated extensively, over some 9 pages, in my book, but what principally concerns us here is the way in which Nimzowitsch keeps switching his attack from the kingside to the queenside and back again, especially starting from move 29. Whilst preparing a breakthrough down the g-file, Nimzo also keeps torturing White with threats against the a2-pawn (29…b5!, allowing a later Qa6, etc). White sets himself up to meet gxf4 by taking with the bishop, keeping things blocked, but Nimzo’s alternation tactics induce some discoordination in the white camp, and the constant switching of the attack between the two flanks eventually sees Black force a collapse of the white defences on the g-file. But then at move 38, just as the kingside looks about to cave in and both white rooks have had to come over to shore up g3, Nimzo switches his queen back to a6 again and calmly lifts the a2-pawn, and it is Black’s passed a-pawn which actually delivers the final blow. A perfect demonstration of two-wing strategy.
By the way, did I mention that my book is available from fine bookstores everywhere?