Shortest-proof-game challenge

Here's a 14.5 move game which requires the annotation Bc2d3. But is it the shortest?

@6094

It is the shortest, but not unique.

Obviously not unique. Black has numerous alternatives for tempo moves.

Bc2xd3#

Here's a 16.5 move game. But is it the shortest?

@6098

Fastest game that ends with cxb8=N# but the knight is not the checking piece.

@6100

Here is one, can be shorter

Here's one way. Could be a shorter way.

@6102

Shorter

#6081

@6104

Shorter

white to move

I wonder if anyone can find the shortest game without checks.

Here is a dubious one. The knight is not the checking piece but a checking piece (double check)

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And here is the ultimate shortest one without double check:

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Here's a proof game, not unique, in 26.0.

Here's a game in 27.5. Leither will tell us how much shorter it needs to be.