BishopTakesH7 wrote:
#6630
First try, 38.5 moves.
Shortest-proof-game challenge
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daStrwbrry wrote:
BishopTakesH7 wrote:
#6630
First try, 38.5 moves.
37.5 after 2+ hours effort.
daStrwbrry wrote:
n9531l1 wrote:
daStrwbrry wrote:
Here are two positions based off an old idea: (#6618)
EDIT: Changed the second position since I saw a dual. I think the first position, although shorter than the other position, is dual-free (unsure about the second position). No intention on beating EvinSung’s proof games though.
Here's one of several SPGs for new version of second position.
At least the first position works. I don’t know if moving the bishop on b5 to a4 resolves the cook in the second position. Although Rh8-a8-a1-e1 is still possible, I think there will be a lot of interferences between the black pieces.
This one is now sound per Stelvio [solving program].
daStrwbrry wrote:
I don’t know if moving the bishop on b5 to a4 resolves the cook in the second position. (#6634)
Unique SPG in 25.0.
n9531l1 wrote:
daStrwbrry wrote:
I don’t know if moving the bishop on b5 to a4 resolves the cook in the second position. (#6634)
Unique SPG in 25.0.
So it is a fix! This might be the furthest I can go with this idea, unless the position after 26. Kxa4 somehow has a unique proof game. If it does, it would certainly make the SPG difficult to find, but I highly doubt it because black has multiple free moves at this point. Could be worth testing though one last time…
daStrwbrry wrote:
n9531l1 wrote:
daStrwbrry wrote:
I don’t know if moving the bishop on b5 to a4 resolves the cook in the second position. (#6634)
Unique SPG in 25.0.
So it is a fix! This might be the furthest I can go with this idea, unless the position after 26. Kxa4 somehow has a unique proof game. If it does, it would certainly make the SPG difficult to find, but I highly doubt it because black has multiple free moves at this point. Could be worth testing though one last time…
Comp says cooked:
BigDoggProblem wrote:
daStrwbrry wrote:
n9531l1 wrote:
daStrwbrry wrote:
I don’t know if moving the bishop on b5 to a4 resolves the cook in the second position. (#6634)
Unique SPG in 25.0.
So it is a fix! This might be the furthest I can go with this idea, unless the position after 26. Kxa4 somehow has a unique proof game. If it does, it would certainly make the SPG difficult to find, but I highly doubt it because black has multiple free moves at this point. Could be worth testing though one last time…
Comp says cooked:
Well, I wasn’t expecting this to be sound, so I will probably stop here. If it were sound, it would be a very difficult SPG to find, which is why I asked to test it. But #6634 should be good enough for me and it doesn’t look like I can extend the proof game any further.
EvinSung wrote:
#6641
45.5 should be shortest, but the white knights could go in either order. Otherwise, the rest seems forced:
EvinSung wrote:
Cooked by Stelvio. 17.5 moves.
EvinSung wrote:
[attempt to extend daStrwbrry's PG 25.0]
Cooked by Stelvio:
Something short and sweet this time
Can you find the unique SPG (tested by Jacobi)?
A better version:
daStrwbrry wrote:
Something short and sweet this time (#6648)
Can you find the unique SPG (tested by Jacobi)?
Another interesting question. How many unique proof games does this position have of different lengths?
daStrwbrry wrote:
A better version:
The "better version" has only one unique proof game, the SPG in 13.0.
n9531l1 wrote:
daStrwbrry wrote:
A better version:
The "better version" has only one unique proof game, the SPG in 13.0.
I thought it was “better” since it was slightly longer than the original and featured a tempo move. The 12.5 proof game in the original also has this tempo move too, but it isn’t the SPG. But then again, “better” is subjective to each person.
Either way, the motif for both positions was that the promoted knight visits all the squares that the b1 knight went to, and returns to that knight’s home (Pronkin N).
Bringing the thread back on topic?! 😉
I reckon 41.5 is fastest.