Rook on the 7th rank
Usually the best place to put a rook in a game is an open file. But sometimes you can do even better like putting them on the 7th rank. Here they can capture pawns, tie down enemy pieces, stop the king from becoming active, and can even threaten mate.
Black to move takes advantage of this to force checkmate. How ?
Video tutorial: Rooks on the 7th rank (9:19 min)
Practise checkmating the king