Shortest-proof-game challenge

Unique SPG in 19.0.

Unique SPG in 25.0.

Finally! I was right about these SPGs being unique. The idea for both positions was the oscillation of the queen, although I was unsure about the 2nd one. I’ve seen this oscillation idea before with knights, rooks, kings, and even bishops in other proof games, but never with queens.

One last position from me. Made slight changes to extend the proof game a bit:

Unique SPG in 27.0.

I remember when you were struggling to find a 22-move unique SPG and when you made it, said you would probably stop there. But you're on a roll now and I wonder if you're thinking about challenging EvinSung's current 41.0 record.

My proof games are merely exploring different themes (e.g. Schnoebelen, Pronkin) rather than going for length. I currently don't have any ideas for an SPG longer than 41.0 moves, nor do I have any plans of doing so. Even if I did try to go for the longest SPG, I would probably end up failing because I would not have enough moves for either side, so I'll leave EvinSung's record alone. However, I do enjoy making these shorter proof games with some thematic play.

I thought #6690 would be my final extension of the oscillating queen, but I just came up with this position. Is this a record for "most oscillations by a queen"?

Unique SPG in 31.0.

Why can't the bRa2 be on a1?

Because the rook could swap a move with the bishop going to a7. But here's the unique 32.5 move version of the position.

Adding those moves stops the Q oscillation, and thus detracts from the main theme.

"Longer" is not always "better".

Beauty is in the eye of the beholder. But if you insist on ending with queen moves, you could at least add 32. Qc2, getting a longer proof game and an extra half-cycle of oscillation. You could even add 32. Qc2 Ng2+ without detracting from the theme.

I don't insist on anything, as it's not my composition.

These are just my opinions on artistic merit.

I prefer the final position with Q back on d1. It would be fine to up it to 33.0 also, etc. and get more full oscillations.

Is this saying that the SPG for this position is cooked? What about the PG (not SPG!) in 32.5 without 33…Ng2+? I initially thought about posting this instead, but there might be Rg8-g1-a1 cooks to save a move for black.

Like @BigDoggProblem, I also like having the queen on her home square. Having complete oscillations seems nicer in my opinion.

The 33.0 PG is cooked. That Rg8-g1-a1 cook works.

It doesn’t work with the 32.5 PG (with Ng2 —> e3) though, so it might be unique. Maybe.

short unique spg?

SPGs in 13.5.