Article 9: The drawn game
9.1      

   1.    A player wishing to offer a draw shall do so after having made a move on the chessboard and before stopping his clock and starting the opponent`s clock. An offer at any other time during play is still valid, but Article 12.6 must be considered. No conditions can be attached to the offer. In both cases the offer cannot be withdrawn and remains valid until the opponent accepts it, rejects it orally, rejects it by touching a piece with the intention of moving or capturing it, or the game is concluded in some other way.

   2.    The offer of a draw shall be noted by each player on his scoresheet with a symbol (See Appendix E13).

   3.    A claim of a draw under 9.2, 9.3 or 10.2 shall be considered to be an offer of a draw. 

9.2      The game is drawn, upon a correct claim by the player having the move, when the same position, for at least the third time (not necessarily by a repetition of moves)

   1.    is about to appear, if he first writes his move on his scoresheet and declares to the arbiter his intention to make this move, or

   2.    has just appeared, and the player claiming the draw has the move.

Positions as in (a) and (b) are considered the same, if the same player has the move, pieces of the same kind and colour occupy the same squares, and the possible moves of all the pieces of both players are the same. Positions are not the same if a pawn that could have been captured en passant can no longer in this manner be captured or if the right to castle has been changed temporarily or permanently.

9.3      The game is drawn, upon a correct claim by the player having the move, if

   1.    he writes his move on his scoresheet, and declares to the arbiter his intention to make this move which shall result in the last 50 moves having been made by each player without the movement of any pawn and without any capture, or

   2.    the last 50 consecutive moves have been made by each player without the movement of any pawn and without any capture.

9.4      If the player makes a move without having claimed the draw he loses the right to claim, as in Article 9.2 or 9.3, on that move.

9.5      If a player claims a draw as in Article 9.2 or 9.3, he shall immediately stop both clocks. He is not allowed to withdraw his claim.

   1.     If the claim is found to be correct the game is immediately drawn.
   2.     If the claim is found to be incorrect, the arbiter shall add three minutes to the opponent`s remaining time. Additionally, if the claimant has more than two minutes on his clock the arbiter shall deduct half of the claimant`s remaining time up to a maximum of three minutes. If the claimant has more than one minute, but less than two minutes, his remaining time shall be one minute. If the claimant has less than one minute, the arbiter shall make no adjustment to the claimant`s clock. Then the game shall continue and the intended move must be made. 

9.6      The game is drawn when a position is reached from which a checkmate cannot occur by any possible series of legal moves, even with the most unskilled play. This immediately ends the game, provided that the move producing this position was legal.

The fifty move rule in chess states that a player can claim a draw if no capture has been made and no pawn has been moved in the last fifty consecutive moves. The relevant part of the official FIDE laws of chess is rule 9.3[1]:

    The game is drawn, upon a correct claim by the player having the move, if

       (a) he writes on his scoresheet, and declares to the arbiter his intention to make a move which shall result in the last 50 moves having been made by each player without the movement of any pawn and without the capture of any piece, or
       (b) the last 50 consecutive moves have been made by each player without the movement of any pawn and without the capture of any piece.

Naturally, if a player writes down his next move as under (a) above, it must not be a pawn move or a capture for a valid claim. Additionally, a claim doesn't have to be made at the first opportunity – it can be made any time when there were no captures or pawn moves in the last fifty moves.

A game is not automatically declared a draw under the fifty move rule – the draw must be claimed by a player on his turn to move. Therefore a game can continue beyond a point where a draw could be claimed under the rule. Theoretically, a game could continue indefinitely under the rules though in practice, when a draw under the fifty-move rule can be claimed, one of the players is usually happy to claim it (Hooper & Whyld 1992).

Black to move would win on the spot.

This is the kind of position I could imagine torturing an opponent with in an allegro finish, but in correspondence ??! I'd say your opponent has pretty bad manners.