It usually involves the strongest side (usually White) having played h4 to gain space and attack the Black King's position (often after a Black g6). To prevent the white pawn's further advance to h5 (and ideally h6) black plays h5. Later, White covers his pawn on h4 with g3 - and voila!
[Answered] Kingside pawn structure
Sort:
I have often seen the following Kingside pawn structure (diagonals with h4 and h5 respectively) in most games played by professionals; could someone explain why it is done so (i.e. the rationale behind it)?