10
votes
Accepted
Hanham Variation Philidor Defense
No. Black cannot reach the Hanham variation (e.g. the Philidor setup with Nd7, Nf6, e5 and sometimes c6) by force.
The modern move order to reach the Hanham variation, however, is 1. e4 d6! 2. d4 Nf6 ...
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8
votes
Marshall Defense 1.d4 d5 2.c4 Nf6 — transpositions
If you don't take on d5, I think the only advantage black has gained is flexibility. That means he can choose his opening according to your move. But you can be almost 100% sure that the opening will ...
- 1,638
8
votes
Accepted
How this game is denoted as French Advanced Variation?
I apologize for posting a comment as an answer, but this is the only way for me to include diagrams, which I find helpful.
You have entered Advanced French defense by transposition.
After 1.e4 d5 2....
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7
votes
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Transposition into KID
It is a matter of choice
Many grandmasters (e.g. world champion Viswanathan Anand) have consistently played 1.c4 e5 with Black. Others favour the KID or other defenses : Hedgehog (with b6), ...
- 16.6k
7
votes
Accepted
Why is 5...Be7 played before ...b5 in the main line of the Closed Ruy Lopez?
After 5....b5 6.Bb3 Be7, white has the strong option to play 7.d4. Now, 7....exd4 is a mistake, as white obtains a big advantage after 8.e5 Ne4 9.Bd5, which was played in Grischuk-Nepomniachtchi (...
- 5,546
6
votes
Accepted
My Transposition Tables implementation slows down Alpha Beta Pruning
Your current implementation just stores on which positions quiesce search was ran. If it was run before, then it skips the position.
But you don't want to skip searching all positions you searched ...
6
votes
Accepted
How to understand which positions result from certain opening
the absence of Black's C pawn and the fight against the D5 square
That's more or less it. This kind of position is most probably the result of a Sicilian. Could it be something else? It can, but the ...
- 28.3k
6
votes
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1. e4 e6 2. d4 c5 - is this opening worth it?
You need to realize that just because someone gave it that name on move two, that it is certainly going to transpose to another opening with a different name. When determining what opening is played, ...
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5
votes
Marshall Defense 1.d4 d5 2.c4 Nf6 — transpositions
Another possible transposition after 3. Nc3:
After 1. d4 d5 2. c4 Nf6 3. Nc3 Nc6 we arrive at a variation of the Chigorin Defense.
A particularly tricky line is the following.
[FEN ""]
[Title "...
- 9,101
5
votes
Accepted
Transposition Tables
When you shut off the engine and turn it back on, its transposition table has been cleared. In order to continue using the saved positions, a database of some sort would be needed. This would keep ...
- 19.9k
5
votes
Accepted
What do QGA players usually play when White doesn't play exactly 1.d4 d5 2.c4?
It is a matter of taste
It depends on what kind of QGA they like to play, but assuming they like the main lines, there is a bunch of standard moves Black wants to get in anyway and that they can play ...
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4
votes
Accepted
How to avoid the Sicilian after 1.e4 d6 2.Nf3?
White can't force you to play the Sicilian. That is completely your choice. After 1. e4 d6 2. Nf3 there is no reason whatsoever that you cannot continue with the Pirc if you so wish by playing 2...g6.
...
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4
votes
How this game is denoted as French Advanced Variation?
As explained in the fine answer by AlwaysLearningNewStuff, you have transposed into the Advanced French.
Such transpositions are common in chess. That's why, if you are assigning an opening to a ...
- 20.9k
4
votes
Accepted
Marshall Defense transposition to Gruenfeld
Black can only transpose to the Grunfeld if you play Nc3, so there are other candidate moves you can try to prove Blacks play is unsound.
(The idea being that we want to play e4 against Nxd5 and Black ...
- 6,111
4
votes
Three-fold repetition and null move
No. You shouldn't count null-move in repetitions because:
Null-move is fake
Null-move artificially creates a repetition when there is none
Your implementation is correct, but you might want to ...
- 22.6k
2
votes
Marshall Defense 1.d4 d5 2.c4 Nf6 — transpositions
Playing 2...Nf6 requires black's willingness to play 3.cxd5 c6 lines, because black really needs a pawn recapture on d5. If he is ok with that and is prepared schematically for the lines arising after ...
- 1,976
2
votes
Most different openings by transpositions?
Another well-known example is the following:
[fen ""]
1. f4 {Bird's Opening} 1... e5 {From Gambit} 2. e4 {King's Gambit} 2... d5 {Falkbeer Counter Gambit} 3. exd5 exf4 {King's Gambit Accepted}
A ...
- 4,241
2
votes
Is there a root tree of openings based on response by Black and vice versa?
I think what you are looking for is something like
https://chesstempo.com/opening-training/
or
https://openings.chessbase.com/
In both cases, you can build opening move trees (either for White or for ...
- 5,949
2
votes
Accepted
Transposition Tables Bug, implementation produces different results
I am not sure I understand your exact code but my guess here is that you return a transposition table result, no matter the depth of the entry. So if you encounter a position and calculate it one ply ...
- 3,646
2
votes
Marshall Defense transposition to Gruenfeld
This is effectively a pawn-down gambit line for Black. If you're going to play it, be psychologically prepared. White does not have to go for the Grunfeld if they don't want to. The key line is 4. Qa4+...
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2
votes
How to understand which positions result from certain opening
The biggest clue is the pawn structure. Allure's first diagram hints that is was a Grunfeld due to the queenside pawns. (Although since there are so many transpositions that the opening can change on ...
- 5,170
2
votes
Help with Negamax using transposition table
I did not check the entire code in detail, however, two things that I noticed are: You seem to be using a generic hash map with a string as key and value. That seems very slow in my eyes, usually one ...
- 3,646
2
votes
Transposition Table eviction policy
You're over-complicating it to the extent it doesn't make sense. You don't change the size of used RAM by "clearing" an entry. Clearing an entry means zeroing or changing the value to ...
- 21
1
vote
Transposition Table eviction policy
I do believe I have come up with an ugly but (hopefully) complete solution to your problem though. What you have to do is keep track of the first irreversible move in every line that happens in search ...
- 366
1
vote
London system move order nuances Qb6 without Nc6
I think White reacted well when the Black Queen came out. As mentioned by koedem, playing Nf3 earlier, specifically 4.Nf3 in both variations, might make sense.
From Black's perspective, 4..Nc6 and 4.....
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1
vote
How to understand which positions result from certain opening
Some positions have clues which at least rule out certain openings, even if they don't identify one specific opening. For example, if a pawn is still at home, then the opening wasn't one in which that ...
- 6,565
1
vote
Transposition into KID
A lot of players play a setup similar to their main response to d4 in order to narrow their rep. Maybe the positions are objectively a little inferior but it gets the player a position they know and ...
- 4,319
1
vote
1. e4 e6 2. d4 c5 - is this opening worth it?
I've toyed with this idea in the past but never played it seriously. If you're okay with the transpositions there is nothing wrong with it at all.
After 1.e4, e6 2. d4, c5 white has three main ...
- 4,319
1
vote
Accepted
Are there any sources of massive transposition tables?
What you're talking about is basically opening books. If an engine has access to hard-set evaluations of common positions fairly early on in the game, then it can play better.
But having a pre-made ...
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