Shortest-proof-game challenge
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RewanDemontay wrote:
The starting position has 20 moves, not 21.
That's true. Do you know the names of all 20 possible first half-moves?
EvinSung wrote:
#5997
Here are two of several solutions in 9.0.
Nov 26, 2023
0
#5966
n9531l1 wrote:
RewanDemontay wrote:
The starting position has 20 moves, not 21.
That's true. Do you know the names of all 20 possible first half-moves?
anyway...
a3 is the anderssen attack
a4 is the ware opening
b3 is the nimzowitsch larsen attack
b4 is the polish opening
c3 is the saragossa opening
c4 is the english opening
d3 is the mieses opening
d4 is the queen's pawn game
e3 is the van't kruijs opening
e4 is the king's pawn game
f3 is the barnes opening
f4 is the bird opening
g3 is the king's fianchetto attack
g4 is the grob attack
h3 is clement's attack
h4 is the kadas opening
Na3 is the sodium attack
Nc3 is the van geet opening
Nf3 is the reti opening
and Nh3 is the amar opening
most of these have other names
n9531l1 wrote:
Arisktotle wrote:
I still have no clue what "Endgame" refers to - probably not "endgames".
Your clue was at #5989. "Endgame" was the short name being used for EndgameEnthusiast2357.
Thx, I misunderstood that as a referral to @Endgame.." to answer the question. Anyways, the rules mentioned in the related post do not exist for SPGs in general. Stipulations with half-moves (like #4.5) are as common as those with full moves. As you know there are also "EPGs" where the number of moves must be exact. I made one with EPG #7.0 which had other solutions in #6.5.
Ilampozhil25 wrote:
6000th
Nope lol
Ilampozhil25 wrote:
n9531l1 wrote:
Do you know the names of all 20 possible first half-moves?
anyway...
most of these have other names
Which move has the most names? I think it could be 1. Nc3:
Dunst Opening, Heinrichsen Opening, Baltic Opening, Van Geet Opening, Sleipnir Opening, Kotrč's Opening, Meštrović Opening, Romanian Opening, Queen's Knight Attack, Queen's Knight Opening, Millard's Opening, der Linksspringer (in English, the Knight on the Left).
Arisktotle wrote:
As you know there are also "EPGs" where the number of moves must be exact. I made one with EPG #7.0 which had other solutions in #6.5.
A while back there was a discussion here about the greatest possible move-length difference between a position's SPG and its SUPG (shortest unique proof game). For your position the difference would be 0.5. The position below has SPG in 3.0 (there are four of them) and SUPG in 4.0, for a difference of 1.0. Do you know of a position with a difference greater than 1.0?
n9531l1 wrote:
Arisktotle wrote:
As you know there are also "EPGs" where the number of moves must be exact. I made one with EPG #7.0 which had other solutions in #6.5.
A while back there was a discussion here about the greatest possible move-length difference between a position's SPG and its SUPG (shortest unique proof game). For your position the difference would be 0.5. The position below has SPG in 3.0 (there are four of them) and SUPG in 4.0, for a difference of 1.0. Do you know of a position with a difference greater than 1.0?
No! I used to in the time when I tried to keep pace with the latest developments. About 2 decades ago I read some articles about the subject with examples. Obviously the theoretical gap maximum is 1.5 as 2.0 would imply you can play an extra move and undo it. But I don't remember if 1.5 is possible! I am both a bad archivist and have an age affected memory which causes me to lose bits of history. Sorry for that.
Arisktotle wrote:
I am both a bad archivist and have an age affected memory which causes me to lose bits of history.
I'm quite familiar with that phenomenon. I would be interested in knowing the gap, which I don't know of any theory to determine, between my age (80) and yours.
Nov 26, 2023
0
#5974
A previous post by n95 (currently #5637) contained a position with a SUPG of 3, with a longer UPG of 4.5. I'm wondering if this would count as a position with a gap of 1.5, since instead of having a SPG and a longer SUPG, both methods are UPGs.
Leither123 wrote:
A previous post by n95 (currently #5637) contained a position with a SUPG of 3, with a longer UPG of 4.5. I'm wondering if this would count as a position with a gap of 1.5, since instead of having a SPG and a longer SUPG, both methods are UPGs.
No. For that position the gap is zero, since the SUPG is also the SPG. For a gap greater than zero the SPG can't be unique.
Arisktotle wrote:
Obviously the theoretical gap maximum is 1.5 as 2.0 would imply you can play an extra move and undo it.
I'm hoping you can help me understand this. You are saying that a position with a non-unique SPG in 8.5 can't have a shortest unique PG in 10.5 or more, but I'm not sure why that is.
For what it's worth, I know a position with a unique SPG in 8.5 and a unique PG in 13.0. For that position the gap is zero, since the SUPG is the SPG.
Nov 26, 2023
0
#5978
My understanding of what Arisktotle said is that either side could move a piece and then move it back to the square it just moved from. Is that correct or completely wrong?
Either way, I would assume that for a gap of 1.5 to be possible, this possibility would need to be stopped, since the side that played the last move has wasted two moves and therefore could have moved a piece and then moved it back to where it started. There's probably many workarounds, but I haven't seen any examples yet. I would love to see a position with a gap of 1.5, if anyone knows of one.
BishopTakesH7 wrote:
#6004
Here's a proof game in 14.0, one of many.
I still have no clue what "Endgame" refers to - probably not "endgames".
Your clue was at #5989. "Endgame" was the short name being used for EndgameEnthusiast2357.