user8201: "Homebase" is where all the surviving pieces are apparently on their starting squares. Here is a very easy new example proof game: can you find the unique shortest game that leads to this position?
[Title "A.Buchanan 26-11-2020: shortest proof game?"]
[FEN "rnbqkbnr/ppppppp1/8/8/8/8/PPPP1P1P/RN2K1NR w - - 0 1"]

Yes c1 is empty!

user15543: For a partial answer, here are a semi-unique sequence sin 11 moves. They are no doubt revealing of the true solution's strategy.
[FEN ""]

1. e4 h5 2. Qxh5 Rxh5 3. g4 Re5 4. Bc4 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. g5 Re1 8. Be6 Rxe6 9. g6 Rxg6+ 10. Kf1 Rh6 11. Ke1 Rh8

Or this.
[FEN ""]

1. e3 h5 2. Qxh5 Rxh5 3. g3 Rh3 4. Bd3 Rxg3 5. Kf1 Rxe3 6. Kg2 Re1 7. Bf5 Rxc1  8. Bg4 Re1 9. Bh3 Re3 10. Kf1 Rxh3 11. Ke1 Rh8

And this.
[FEN ""]

1. e4 h5 2. Qxh5 Rxh5 3. g3 Re5 4. Bh3 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. Kf3 Re1  8. Kg2 Re3 9. Kf1 Rxg3 10. Ke2 Rxh3 11. Ke1 Rh8


user24693: I have no idea about this kind of problems, but my guess would be something like this.
[FEN ""]

1. g4 h5 2. Bg2 hxg4 3. Bf3 gxf3 4. Kf1 fxe2+ 5. Kg2 exd1=R 6. Kf3 Rxc1 7. Ke2 Re1+ 8. Kxe1

Is that unique? I have no idea.

8201: <p>&quot;Homebase&quot; is where all the surviving pieces are apparently on their starting squares. Here is a very easy new example proof game: can you find the unique shortest game that leads to this position?</p>
<pre><code>[Title &quot;A.Buchanan 26-11-2020: shortest proof game?&quot;]
[FEN &quot;rnbqkbnr/ppppppp1/8/8/8/8/PPPP1P1P/RN2K1NR w - - 0 1&quot;]
</code></pre>
<p>Yes c1 is empty!</p>
 15543: <p>For a partial answer, here are a semi-unique sequence sin 11 moves. They are no doubt revealing of the true solution's strategy.</p>
<pre><code>[FEN &quot;&quot;]

1. e4 h5 2. Qxh5 Rxh5 3. g4 Re5 4. Bc4 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. g5 Re1 8. Be6 Rxe6 9. g6 Rxg6+ 10. Kf1 Rh6 11. Ke1 Rh8
</code></pre>
<p>Or this.</p>
<pre><code>[FEN &quot;&quot;]

1. e3 h5 2. Qxh5 Rxh5 3. g3 Rh3 4. Bd3 Rxg3 5. Kf1 Rxe3 6. Kg2 Re1 7. Bf5 Rxc1  8. Bg4 Re1 9. Bh3 Re3 10. Kf1 Rxh3 11. Ke1 Rh8
</code></pre>
<p>And this.</p>
<pre><code>[FEN &quot;&quot;]

1. e4 h5 2. Qxh5 Rxh5 3. g3 Re5 4. Bh3 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. Kf3 Re1  8. Kg2 Re3 9. Kf1 Rxg3 10. Ke2 Rxh3 11. Ke1 Rh8
</code></pre>
 24693: <p>I have no idea about this kind of problems, but my guess would be something like this.</p>
<pre><code>[FEN &quot;&quot;]

1. g4 h5 2. Bg2 hxg4 3. Bf3 gxf3 4. Kf1 fxe2+ 5. Kg2 exd1=R 6. Kf3 Rxc1 7. Ke2 Re1+ 8. Kxe1
</code></pre>
<p>Is that unique? I have no idea.</p>
