user11144: Duh.
Clearly, the one shown there with Qxh5+ Rxh5# can be easily turned into a s#2, by e.g. B-e2-f3, Qe2 from White and c6, Q-a5xd2-d1 from Black. 9.0 moves if I added correctly. Someone care to beat this, or even construct a helpgame-s#3? (This might be far trickier than a #n counterpart!)
Addendum: This example doesn't work as the Black queen vacates d8 for the Black king.

user15543: I care to do it in 7.0 moves.
[FEN ""]

1. f4 e5 2. Kf2 Ke7 3. Kg3 Kf6 4. Kh4 Kf5+ 5. Kh5 e4 6. e3 d5 7. h4 Qe7 8. Qg4+ Kf6 9. Qg6+ fxg6#


11144: <p><a href="https://chess.stackexchange.com/questions/33168/the-quickest-selfmate-in-1">Duh.</a></p>
<p>Clearly, the one shown there with Qxh5+ Rxh5# can be easily turned into a s#2, by e.g. B-e2-f3, Qe2 from White and c6, Q-a5xd2-d1 from Black. 9.0 moves if I added correctly. Someone care to beat this, or even construct a helpgame-s#3? (This might be <em>far</em> trickier than a <a href="https://chess.stackexchange.com/questions/36788/the-fastest-dualed-mates-in-n">#n</a> counterpart!)</p>
<p>Addendum: This example doesn't work as the Black queen vacates d8 for the Black king.</p>
 15543: <p>I care to do it in 7.0 moves.</p>
<pre><code>[FEN &quot;&quot;]

1. f4 e5 2. Kf2 Ke7 3. Kg3 Kf6 4. Kh4 Kf5+ 5. Kh5 e4 6. e3 d5 7. h4 Qe7 8. Qg4+ Kf6 9. Qg6+ fxg6#
</code></pre>
