Rook mate
Mating with king and rook versus king takes a little more work than with the queen: here the kings must stand directly opposite each other, in opposition, before the rook can give the decisive check.
Try to deliver the mate
Your turn: find the move that delivers checkmate. Drag the piece to the right square.
How to deliver it
The kings stand in opposition: directly opposite each other with one square between. Your king on e6 covers all the squares in front of the black king, so the rook sweeps to a8 and mates along the back rank. The king has nowhere to go. Checkmate.
How to defend
As the defender you keep your king toward the centre as long as you can, because the closer it is pushed to the edge, the closer the mate. And as with the queen mate: keep an eye out for stalemate. A careless rook move can let you escape with a draw.