user3131: I want to know which international game has the longest sequence of forced moves until checkmate, even if the opponent resigned the game. The result should not be drawn, i.e. we should consider 50 move rule).

user12402: Alekhine - Yates
http://www.chessgames.com/perl/chessgame?gid=1012179
19 moves.  Alekhine resigned a couple of moves before mate.

3131: <p>I want to know which international game has the longest sequence of forced moves until checkmate, even if the opponent resigned the game. The result should not be drawn, i.e. we should consider 50 move rule).</p>
 12402: <p>Alekhine - Yates
<a href="http://www.chessgames.com/perl/chessgame?gid=1012179" rel="nofollow noreferrer">http://www.chessgames.com/perl/chessgame?gid=1012179</a></p>

<p>19 moves.  Alekhine resigned a couple of moves before mate.</p>
