user21526: I tried to get the smallest sequence of moves that would result in a checkmate*( or rather Helpmate)* with the last move being a en passant . This is the shortest I could get :
[Title "Shortest En Passant Helpmate?"]
[fen ""]

1. e4 f6 2. Qe2 Kf7 3. e5 Ke6 4. Qe4 Nc6 5. Be2 Nb8 6. Nc3 Nc6 7. Nb5 Nb8 8. Nf3 Nc6 9. d3 Kf7 10. Nfd4 Nb8 11. Nb3 Nc6 12. Na5 Nb8 13. Nc4 Nc6 14. Nb6 Ke6 15. Bh5 Nb8 16. O-O d5 17. exd6#

Is there a shorter way to achieve it or 13 is the limit ?

user11749: I found one in 8 moves:
[Title "Shortest En Passant Helpmate?"]
[fen ""]

1. e4 f6 2. Bb5 Kf7 3. Qe2 Ke6 4. e5 Qe8 5. Qe4 Qf7 6. d4 a6 7. Bf4 d5 8.exd6#


21526: <p>I tried to get the smallest sequence of moves that would result in a checkmate*( or rather Helpmate)* with the last move being a en passant . This is the shortest I could get :</p>

<pre><code>[Title "Shortest En Passant Helpmate?"]
[fen ""]

1. e4 f6 2. Qe2 Kf7 3. e5 Ke6 4. Qe4 Nc6 5. Be2 Nb8 6. Nc3 Nc6 7. Nb5 Nb8 8. Nf3 Nc6 9. d3 Kf7 10. Nfd4 Nb8 11. Nb3 Nc6 12. Na5 Nb8 13. Nc4 Nc6 14. Nb6 Ke6 15. Bh5 Nb8 16. O-O d5 17. exd6#
</code></pre>

<p>Is there a shorter way to achieve it or 13 is the limit ?</p>
 11749: <p>I found one in 8 moves:</p>

<pre><code>[Title "Shortest En Passant Helpmate?"]
[fen ""]

1. e4 f6 2. Bb5 Kf7 3. Qe2 Ke6 4. e5 Qe8 5. Qe4 Qf7 6. d4 a6 7. Bf4 d5 8.exd6#
</code></pre>
