Passed pawns become a real pain, not only in the neck but everywhere else....

Openings are just a guide for the basic on how a proper game is meant to be started. Beyond that, imagine a river running right in the centre of the board separating your and the opposing side. Any piece of your opponent that crosses the river over to your side IS A BREACH and if ignored,it will be reinforced and ultimately lead to your downfall!

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At the advanced level, CHESS involves intricacies of fine art - in unravelling of the  opponents defences.