user16626: Black legally moves a pawn to the 8th rank, intended to promote it to a queen without specifying what piece this pawn should be promoted to. White immediately captured the pawn with his piece (as it is the only "reasonable" move in this position) without waiting for black to finish his promotion.
Did white make an illegal move here? Is white obligated to wait for black to complete the promotion before making the capture, even if his only reasonable move is to capture the promoted piece?
Edit This happened in a game without time control; so no chess clock was used.

user12629: I'm going to assume for the sake of argument that White has pressed the clock after doing this. (According to article 7.5.1, "An illegal move is completed once the player has pressed his clock" so it would seem that this is a requirement for an illegal move.)
According to the FIDE Laws of Chess article 4.7:

The move is considered to have been made in the case of...
4.7.3  promotion, when the player's hand has released the new piece on the square of promotion and the pawn has been removed from the board.

So the previous move has not been "made" yet. And according to article 1.2:

The player with the light-coloured pieces (White) makes the first move, then the players move alternately...

Black has not yet "made" their move, so White is not moving alternately, which is in violation of the rules.
But not every rule violation is an illegal move. "Illegal move" has a definition:

3.10.1     A move is legal when all the relevant requirements of Articles 3.1 – 3.9 have been fulfilled.
3.10.2     A move is illegal when it fails to meet the relevant requirements of Articles 3.1 – 3.9

Strictly speaking, the requirement to move alternately is not mentioned in 3.1 - 3.9. It's in 1.2.
But, 7.5.3 states:

If the player presses the clock without making a move, it shall be considered and penalized as if an illegal move.

Now the question becomes: Has White made a move? I would say that no, you cannot make a move if you do not "have the move". I would therefore say that White has pressed the clock without making a move.
So, in conclusion, White shall be considered and penalized as if they had made an illegal move.

16626: <p>Black legally moves a pawn to the 8th rank, intended to promote it to a queen without specifying what piece this pawn should be promoted to. White immediately captured the pawn with his piece (as it is the only &quot;reasonable&quot; move in this position) without waiting for black to finish his promotion.</p>
<p>Did white make an illegal move here? Is white obligated to wait for black to complete the promotion before making the capture, even if his only reasonable move is to capture the promoted piece?</p>
<p><strong>Edit</strong> This happened in a game without time control; so no chess clock was used.</p>
 12629: <p>I'm going to assume for the sake of argument that White has pressed the clock after doing this. (According to article 7.5.1, &quot;An illegal move is completed once the player has pressed his clock&quot; so it would seem that this is a requirement for an illegal move.)</p>
<p>According to the <a href="https://handbook.fide.com/chapter/E012018" rel="nofollow noreferrer">FIDE Laws of Chess</a> article 4.7:</p>
<blockquote>
<p>The move is considered to have been made in the case of...<br />
4.7.3  promotion, when the player's hand has released the new piece on the square of promotion and the pawn has been removed from the board.</p>
</blockquote>
<p>So the previous move has not been &quot;made&quot; yet. And according to article 1.2:</p>
<blockquote>
<p>The player with the light-coloured pieces (White) makes the first move, then the players move alternately...</p>
</blockquote>
<p>Black has not yet &quot;made&quot; their move, so White is not moving alternately, which is in violation of the rules.</p>
<p>But not every rule violation is an illegal move. &quot;Illegal move&quot; has a definition:</p>
<blockquote>
<p>3.10.1     A move is legal when all the relevant requirements of Articles 3.1 – 3.9 have been fulfilled.<br />
3.10.2     A move is illegal when it fails to meet the relevant requirements of Articles 3.1 – 3.9</p>
</blockquote>
<p>Strictly speaking, the requirement to move alternately is <em>not</em> mentioned in 3.1 - 3.9. It's in 1.2.</p>
<p>But, 7.5.3 states:</p>
<blockquote>
<p>If the player presses the clock without making a move, it shall be considered and penalized as if an illegal move.</p>
</blockquote>
<p>Now the question becomes: Has White made a move? I would say that no, you cannot make a move if you do not &quot;have the move&quot;. I would therefore say that White has pressed the clock without making a move.</p>
<p>So, in conclusion, White shall be considered and penalized as if they had made an illegal move.</p>
