15. ... Nxd7
Black attempts to hold on to his material advantage, but he misses a beautiful sacrifice that leads to mate.
16. Qb8+!
Normally, sacrificing your queen is not recommended! On the other hand, the king is a much bigger target than the queen, and this move leads to a forced checkmate.
16. ... Nxb8
Capturing the queen is the only way to avoid checkmate.
17. Rd8#
Black is checkmated; the king cannot capture White's rook, which is protected by the bishop on g5. The final position can be seen on the next page.
