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| (1) Posted by Viktoras Paliulionis [Wednesday, Sep 27, 2023 22:31] |
The arrival effect needs a name
https://yacpdb.org/#461566
Onkoud, Abdelaziz
Best Problems, 2016 (78/3618)
 (= 6+4 )
h#2
1...Rxc4+ 2.Sxc4 Bb5 3.Se3 Bd3#
1...Bxd5+ 2.Sxd5 Rb5 3.Sf4 Re5#
The purpose of White's first move is to enable bS to move to the square on which bP stands.
In the Helpmate Analyzer, the arrival effect at W1 is called "Unblock by capture".
I think the term "unblock" is not appropriate here, because by definition, "unblock is the removal of a friendly piece so that the king may occupy that square".
Also, it is not clear from the name that W1 is a sacrificial move.
I would like to find a more precise name for this effect.
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| (2) Posted by shankar ram [Thursday, Sep 28, 2023 08:51] |
Annihilation?
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| (3) Posted by Georgy Evseev [Thursday, Sep 28, 2023 10:45] |
The term "vacation" is generally used when a piece leaves square to allow another one move there.
Maybe, "Vacation by capture"?
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| (4) Posted by Jacques Rotenberg [Thursday, Sep 28, 2023 11:23] |
perhaps :
'line opening by sacrifice"
it opens a line for white and a line for black
the black lines are
b6-d5-f4 ans b6-c4-e3
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| (5) Posted by Viktoras Paliulionis [Thursday, Sep 28, 2023 11:23] |
According to the meaning of the term "vacation", the square should be empty after the vacation.
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| (6) Posted by shankar ram [Thursday, Sep 28, 2023 11:29] |
>>> ...by definition, "unblock is the removal of a friendly piece so that the king may occupy that square"
This definition is too restrictive.
Squares may be unblocked for non-royal pieces by removal of friendly pieces.
Or in the case of pawns (or in fairies, non-capturing pieces like Chinese pieces), squares may be unblocked by enemy pieces too.
The word "obstruction" is also used for the opposite effect.
But I can't recall "unobstruction" being used anywhere!
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| (7) Posted by Hauke Reddmann [Thursday, Sep 28, 2023 11:53] |
Personally, I would use "annihilation" (which is the prime motive)
together with a qualifier for the purpose, e.g.:
Flight annihilation - the bK needs the square to walk to
Reblock annihilation - the blocking piece must be replaced by another
which lacks the bad side effects: unguard, unpin... (What is meant
with the quoted item from Helpmate Analyzer?!)
Active gate annihilation - blocking piece can't let a (white - but
black is also possible) piece pass through (the example given here)
Passive gate annihilation - blocking piece can't open a white line,
a recent example is Schwalbe 19243 (P1412417)
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| (8) Posted by Viktoras Paliulionis [Thursday, Sep 28, 2023 12:31] |
The term "annihilation" is used in the Helpmate Analyzer to a different effect.
According to the FIDE Album (as well as other sources), an "annihilation" is a capture of a piece followed by a move of the capturing piece from this square, resulting in a positive effect arising from the disappearance of the captured piece (usually line-opening or vacation of the square).
In the case of annihilation, an important point is that the capturing piece must leave the square. In my example, the annihilation occurs on Black's first move. After capturing wB, bS leaves this square on second move, opening the line for white piece.
Capture with a white piece (on W1) and with a black piece (on B2) have different motives, so they should be called differently.
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| (9) Posted by Jacques Rotenberg [Thursday, Sep 28, 2023 12:40] |
"annihilation" is possible... but it is better when followed by a switchback of the capturing unit or at least a passive move
that's why I propose "white sacrifice for opening two lines, one black and one white"
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| (10) Posted by Hauke Reddmann [Thursday, Sep 28, 2023 12:58] |
@Viktoras: I see (I'm not familiar with the nomenclature).
Then s/annihilation/capture/ and keep the rest?
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| (11) Posted by Georgy Evseev [Thursday, Sep 28, 2023 13:15] |
From the other hand, this is simply "Sacrifice with capture".
There may be a number of motivations for such sacrifiсe.
For example, does HA has a specific term when the sacrifice is made to prepare the shelter for hideaway? In fact, the logic is very similar: white ensure that black can now play to a specific square.
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| (12) Posted by Jacques Rotenberg [Thursday, Sep 28, 2023 14:27] |
in fact you can argue that it is opening a black line only, because, in 3 moves the rook can reach e5 with b4-b5xd5-e5, so the whole necessity of the sacrifice is to give the knight access to f4
the same in the other solution
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| (13) Posted by Viktoras Paliulionis [Thursday, Sep 28, 2023 16:36] |
@Jacques,
Line opening and accessing the knight to f4 is the ultimate purpose of the overall maneuver, not a single move.
Individual maneuver moves can have different effects within the maneuver.
In the following examples, W1 have the same effect, although the further play of bS is different:
1.
 (= 3+8 )
1...Bxd5+ 2.Sxd5 Kf2 3.Sf4 Sf6#
2.
 (= 4+8 )
1...Bxd5+ 2.Sxd5 Ke2 3.Sxf6 Sxf6#
3.
 (= 4+11 )
1...Bxd5+ 2.Sbxd5 Rb5 3.Sf6 Rxe5#
I need an effect name for W1 that fits all such cases.
BTW in the example No.2, 3.Sxf6 has the same effect as 1...Bxd5.
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| (14) Posted by Frank Richter [Thursday, Sep 28, 2023 16:49] |
Possibly "Capture of a black/white square block"?
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| (15) Posted by Viktoras Paliulionis [Thursday, Sep 28, 2023 18:37] |
@shankar ram:
QUOTE
>>> ...by definition, "unblock is the removal of a friendly piece so that the king may occupy that square"
This definition is too restrictive.
Squares may be unblocked for non-royal pieces by removal of friendly pieces.
Or in the case of pawns (or in fairies, non-capturing pieces like Chinese pieces), squares may be unblocked by enemy pieces too.
The word "obstruction" is also used for the opposite effect.
But I can't recall "unobstruction" being used anywhere!
"Unblock" is an antiform of "self-block".
For non-royal pieces, a good term is "square vacation".
The opposite effect to "square vacation" is "square obstruction".
"Unblock" is a special type of "square vacation".
I think it's good that terms self-block and unblock have a narrow meaning. These effects are very often used in helpmates. The short name is clear to everyone without further explanation.
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| (16) Posted by Jacques Rotenberg [Thursday, Sep 28, 2023 19:10] |
@ Viktoras
"...Line opening and accessing the knight to f4 is the ultimate purpose of the overall maneuver, not a single move..."
I am not sure I understand what you mean.
In your examples 1 and 2 the reason why the Bishop is sacrificed is exactly the same : to open the knight's way. If the moves of the knight are c3-d5-f4 or c3-d5-f6, it does not change, the sacrifice of the Bishop is made to let the knight go to its final destination.
Your example 3 is different : the knight has access to its final destination in two moves so the whole maneuver is the open the line of the white rook.
The bishop does not do the job, it just gives the knight the possibility to open the line of the rook
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| (17) Posted by Nikola Predrag [Thursday, Sep 28, 2023 19:12] |
It's pretty obvious :-) :
(self-)sacrificial color-change (on the square), enabling - the (capturing) play in B2 towards - the squareblock in B3 which includes line-opening for W3.
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| (18) Posted by Georgy Evseev [Thursday, Sep 28, 2023 20:50] |
Maybe, based on Jacques's idea, use "Path clearance/vacation sacrifice", as this is obviously not the line.
See, for example, WInChloe: 832536, 862318, 875165, 880814, 893790 and many others.
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| (19) Posted by Jacques Rotenberg [Thursday, Sep 28, 2023 22:09] |
@Georgy
I would say : for me a line is a series of ordered squares where interceptions may occur.
This line may need several steps and so does not need to be a "straight" line.
If you want to call that a "path" it is ok for me... I just don't feel the necessity for a new word
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| (20) Posted by Viktoras Paliulionis [Thursday, Sep 28, 2023 22:49] |
@Jacques:
QUOTE
"...Line opening and accessing the knight to f4 is the ultimate purpose of the overall maneuver, not a single move..."
I am not sure I understand what you mean.
My point is that wB move motivation is just to allow bS to move to the blocked square (in all examples). Subsequent moves of bS have different motivations. The white bishop doesn't care what the black knight does when he gets to the d5 square. Each move plays its own little role in the overall maneuver. The arrival effect of the move should describe only this little role.
@Nikola:
QUOTE
It's pretty obvious :-) :
(self-)sacrificial color-change (on the square), enabling - the (capturing) play in B2 towards - the squareblock in B3 which includes line-opening for W3.
I think you're right, but only until the last part.
The last part describes the effect of the last bS move, not wB. For wB this is only a secondary effect.
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