Underpromotion

Thanks for sending this, Nikola!

Lawrence Day vs Jan Timman
Day, LA . 1980
Hungarian Opening: General [A00]

This is a beautiful example of underpromotion saving the day in a real game. If White promotes the pawn to anything other than a knight, Rh1 is checkmate. If White doesn't move the pawn, but instead moves the king, Black takes the pawn and wins.

Sneaky "checked this with 'Tablebase' to see if either Day or Timman made any mistakes after 71.g8=N+! and I found that their play was perfect from that point on. I know that there are some rare positions where a rook can beat a knight, and they all have to do with a king trapped on the edge or in the corner like in this game, but [Day] played it perfectly. To give [Timman] his due, he forced [Day] to find a few 'only moves' along the way to the game's rightful conclusion."

The rest of the game:

→ PGN

Source: ChessGames.com