Sacrificing to force mate is an important idea to know about. The rook sacrifice draws the king closer and there is no escape. The example below is from the recent 2018 BC Closed championship.
White to move
Easy stuff: 1.Rh8+ Kxh8 2. Qh4+ Kg8 3. Qh7+ Kf8 4. Qh8 mate.
NCM Vas Sladek
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