Black: In Place

The final hurdle — and my signature number again, now as Black. The king has already dug in on g8, his final square, so during castling he won't stir: all the work goes to the rook, which jumps from h8 to f8. Remember: even when only one piece moves, it's a full-fledged castling, in one gesture. King — onto the rook h8, and the trainer is yours!