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Question for the rules experts: more-squares rule and repeated positions


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#1 TemplateRex

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Posted 20 September 2018 - 07:57 AM

11. Repetition of Threatening Moves: MoreSquares Rule

11.1 It is not allowed to continuously chase one or more pieces of the opponent endlessly. The continuous chaser may not play a chasing move which would lead to a position on the board which has already taken place.

What does the phrase "a position on the board which has already taken place" mean exactly?

  • Any position in the history of the game?
  • A position in the current chasing sequence?

Take e.g. the following position with red to move:

mjTc0eh.png

After

1. c8-a8              b9-a9 (chase)
2. a8-b8 (evade) a9-b9 (chase)
3. b8-c8 (evade) b9-d9
4. c8-b8              d9-b9 (chase)
5. b8-a8 (evade) b9-a9 (chase)

is it allowed for blue to play 5... b9-a9?

Under interpretation 1), it would not be allowed since the same position has taken place already after blue's first move.
Under interpretation 2), it would be allowed, since the position has not taken place already in the same chasing sequence.

What do the rules experts say? What was the intent of the ISF rule and what is the letter?

EDIT: Vincent de Boer writes in his thesis (p. 113)

In short that means you are not allowed to do a move that would lead to a situation on the board that has already taken place during an uninterrupted sequence of threatening moves. After a single non-threatening move, all history is thrown away and all moves are allowed again.

So he adheres to interpretation 2). To me, the language of the ISF-rule is insufficiently clear, though.


Edited by TemplateRex, 22 September 2018 - 10:05 AM.

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#2 DeepLimbo

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Posted 21 September 2018 - 01:58 PM

I don't now the intent of the rule, but for me the letter is clear.

 

The phrase starts with "The continuous chaser may not..." So the continuous chaser is the subject of the sentence. Nothing is said about the non-continuous chaser, so this rule does not apply to him. Therefore it is a safe assumption that he is allowed to play a (chasing) move which would lead to a position on the board which has already taken place. So I tend to agree with Vincent de Boer.



#3 Napoleon 1er

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Posted 21 September 2018 - 03:21 PM

If i were red i would play c8-c10 ... smile!
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#4 GaryLShelton

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Posted 21 September 2018 - 09:00 PM

There's a lot of things about the ISF rules that aren't perfectly clear. The Two Squares Rule as it applies to scouts (10.2) is one of them.

Here the chase has been broken so, yes in my opinion, the blue scout could return to a9 in the question.

i77rs4m.jpg

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#5 TemplateRex

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Posted 21 September 2018 - 09:17 PM

I don't now the intent of the rule, but for me the letter is clear.

 

The phrase starts with "The continuous chaser may not..." So the continuous chaser is the subject of the sentence. Nothing is said about the non-continuous chaser, so this rule does not apply to him. Therefore it is a safe assumption that he is allowed to play a (chasing) move which would lead to a position on the board which has already taken place. So I tend to agree with Vincent de Boer.

 

OK, I extended the initial sequence by one move, so that red plays c8-b8-a8 on the second sequence, and the question then is can blue play b8-a8, even when b8-a8 continues the chase and leads to a repeated position (but this position only happened in a previous chase sequence).


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#6 TemplateRex

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Posted 21 September 2018 - 09:18 PM

If i were red i would play c8-c10 ... smile!

 

still only a draw if blue continues to play b9-b8-b7 when red is on the 10th row, but otherwise, put a bomb on c10 :)


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#7 TemplateRex

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Posted 21 September 2018 - 09:20 PM

There's a lot of things about the ISF rules that aren't perfectly clear. The Two Squares Rule as it applies to scouts (10.2) is one of them.

Here the chase has been broken so, yes in my opinion, the blue scout could return to a9 in the question.

 

i updated the example by letting red play c8-b8-a8 and the question is can blue chase d9-b9-a9? There is a continuous chase, and there is a repeated position, but the position only happened in a previous chase.


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#8 GaryLShelton

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Posted 21 September 2018 - 10:37 PM

I think you meant to say b9-d9 in step three for blue. But regardless, the move to a9 will be permitted for the same reason as before. The chase has been broken and you are in a new sequence.

In the SMT (Square Moved To)* chase blocking programming that The Prof and myself offered a few years ago this would be allowed for the same reason. But we spell it out clearly in both our SMT and RBP (Repeated Board Position) language that it only goes back to the beginning of a chase sequence.

* A few years ago, back in 2014, The Prof and myself offered up to the ISF our version of Articles 10 and 11 (expected to change to 11 and 12) for purposes of clarifying the English and making an improvement to the RBP blocking mechanism in use by the ISF. See our Article 11/12 offering at the following link. (Scroll up for Article 10/11.)

http://forum.strateg...884#entry428884

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#9 TemplateRex

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Posted 22 September 2018 - 10:44 AM

I just played out this position on Gravon with two non-registered accounts RedAnalysis and BlueAnalysis. 

 

fNCuXM4.jpg

 

The left diagram shows red's last move, and the right diagram shows what Gravon says when trying to make the blue move B9-A9

 

* This move would violate the more-squares-rule. You may not continously chase one or more pieces of your opponent without beating one.

 

So on Gravon they adhere to interpretation 1: it is not allowed to repeat a position during a continuous chase, even if the repetition occurred in a previous chase and not in the current one.


Edited by TemplateRex, 22 September 2018 - 10:45 AM.

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#10 TemplateRex

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Posted 22 September 2018 - 01:04 PM

Another example: the famous Enigma-ABSH draw refusal case (original case, Notrom's claimexplanation by The Prof), with the following position to illustrate how two top pieces can correctly defend against 4 (or more) scouts 

 

RJ1D3Ag.jpg

 

The idea (explained by the Prof) is to play as red

 

1. A2-A3 (chase) B3-B2 (evade)

2. B1-C1 (chase) C2-C3 (evade)

3. A3-A2 (chase) B2-B3 (evade)

4. C1-B1              C3-C2

 

and we're back to square one (pun intended). However, if red now plays

 

5. A2-A3 (chase) B3-B2 (evade, see right diagram below)

 

the Gravon site will forbid red from continuing with 6. B1-C1  (see text below left diagram below) since it is a continuously chasing move into a repeated position, regardless of whether the repetition happened in the current or in a previous chasing sequence.

 

wn3bZt6.jpg

 

So on Gravon, red is lost in the initial position :)

 

 


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#11 GaryLShelton

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Posted 23 September 2018 - 07:45 AM

The left diagram shows red's last move, and the right diagram shows what Gravon says when trying to make the blue move B9-A9
 

 
So on Gravon they adhere to interpretation 1: it is not allowed to repeat a position during a continuous chase, even if the repetition occurred in a previous chase and not in the current one.

.

TR, what they say is simply in error. Gravon, despite being run by a member of the ISF, one Dieter Krapp, is not perfect on its programming of the ISF rules. For one, when you are not continuously chasing, as you are not here, then you are not continuously chasing. For two, there is nothing in the ISF rules about "beating" a piece being necessary to break a chasing sequence by the chaser. One merely has to stop chasing.

The use of "beat" is interesting because it's the same word Herr Krap used with myself and The Prof to explain why a scout could not threaten a Marshal...it could not "beat" it, which is pretty much what you call utter nonsense. Just because a piece is inferior does not mean it can't threaten a superior piece and therefore even chase a piece. Who among us hasn't chased a known Colonel or General with an unknown but inferior piece? Besides, with an inferior piece the goal is often not to capture/"beat" but merely to gain information on an unknown piece. Whether a chasing piece is superior is irrelevant to the fact of whether it can chase another piece.

When I get back home from traveling Monday and on a desktop I'm going to post my poll on scout movement. It's a subject that, again, Gravon had programmed wrong when we checked, and likely still does. Believe it or not, this site has the correct programming with regards to scout movement rules and Gravon wrong.

i77rs4m.jpg

The complete GS&F Rules can be found here: http://forum.strateg...rum-rules-2016/

Draw Refusal Rules, specifically, can be read here: http://forum.strateg...931#entry468931


#12 GaryLShelton

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Posted 23 September 2018 - 03:32 PM

Another example: the famous Enigma-ABSH draw refusal case (original case, Notrom's claimexplanation by The Prof), with the following position to illustrate how two top pieces can correctly defend against 4 (or more) scouts 
 
RJ1D3Ag.jpg
 
The idea (explained by the Prof) is to play as red
 
1. A2-A3 (chase) B3-B2 (evade)
2. B1-C1 (chase) C2-C3 (evade)
3. A3-A2 (chase) B2-B3 (evade)
4. C1-B1              C3-C2
 
and we're back to square one (pun intended). However, if red now plays
 
5. A2-A3 (chase) B3-B2 (evade, see right diagram below)
 
the Gravon site will forbid red from continuing with 6. B1-C1  (see text below left diagram below) since it is a continuously chasing move into a repeated position, regardless of whether the repetition happened in the current or in a previous chasing sequence.
 
wn3bZt6.jpg
 
So on Gravon, red is lost in the initial position :)

.

This is a good look back at things, TR. It's a wonderful bit of research to dig it all up and reconstruct it. :) Just to point out for clarity, the famous Enigma/ABSH case where the MT convicted ABSH more or less wrongly did not feature 4 scouts but rather only 2. I'm unable to view the imageshack pics from Enigma to verify their exact positions but I'm not sure if that's because they are expired (likely), or that I'm just on my phone today. The Nortrom example was to show that even 8 scouts would still end up a draw. The Prof explained that it wouldn't matter beyond four scouts. That either here or with the ISF the situation would still be a draw.

With your analysis of this, TR, the one thing that is clear is that Gravon's programming differs from what both Nortrom and The Prof have determined the proper outcome should be. At Gravon the programming would evidently have given the game to Enigma and for the total game memory as opposed to just the current chasing sequence as you state, though that's awfully quick to block in my mind.

I personally would find this an incorrect programming as well.


Just to highlight it, and to repeat something The Prof stated at that link above, no piece is chased unless it evades immediately after the threatening piece moves into a full-bind with it. So if a piece does not evade, it is not being chased, as is the case with some of the scouts in the four scout example.

i77rs4m.jpg

The complete GS&F Rules can be found here: http://forum.strateg...rum-rules-2016/

Draw Refusal Rules, specifically, can be read here: http://forum.strateg...931#entry468931


#13 TemplateRex

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Posted 23 September 2018 - 04:05 PM

.

This is a good look back at things, TR. It's a wonderful bit of research to dig it all up and reconstruct it. :) Just to point out for clarity, the famous Enigma/ABSH case where the MT convicted ABSH more or less wrongly did not feature 4 scouts but rather only 2. I'm unable to view the imageshack pics from Enigma to verify their exact positions but I'm not sure if that's because they are expired (likely), or that I'm just on my phone today. The Nortrom example was to show that even 8 scouts would still end up a draw. The Prof explained that it wouldn't matter beyond four scouts. That either here or with the ISF the situation would still be a draw.

 

Yes, I also couldn't find the exact image. The description from The Prof (linked in my post) seems to correspond to the diagram shown. 

With your analysis of this, TR, the one thing that is clear is that Gravon's programming differs from what both Nortrom and The Prof have determined the proper outcome should be. At Gravon the programming would evidently have given the game to Enigma and for the total game memory as opposed to just the current chasing sequence as you state, though that's awfully quick to block in my mind.

I personally would find this an incorrect programming as well.
 

For what it's worth, all the computer programs at the 2008-2010 world computer championships reset the memory buffer as soon as a chasing sequence is being broken. I am also sympathetic to this interpretation, but I think the ISF rule as it stand is ambiguous about it.

Just to highlight it, and to repeat something The Prof stated at that link above, no piece is chased unless it evades immediately after the threatening piece moves into a full-bind with it. So if a piece does not evade, it is not being chased, as is the case with some of the scouts in the four scout example.

 

If you threaten multiple pieces (as red does in this example), only one piece can evade of course. And indeed, after every threatening move by red, blue evades at least one piece. Only if red would have captured the non-evading piece, then the chasing sequence would have been broken. I hope we can all agree on that?


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#14 TemplateRex

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Posted 23 September 2018 - 04:23 PM

.

TR, what they say is simply in error. Gravon, despite being run by a member of the ISF, one Dieter Krapp, is not perfect on its programming of the ISF rules. For one, when you are not continuously chasing, as you are not here, then you are not continuously chasing. For two, there is nothing in the ISF rules about "beating" a piece being necessary to break a chasing sequence by the chaser. One merely has to stop chasing.

 

In German the text is:

 

"* Dieser Zug w├╝rde die Mehrfeldregel verletzen. Du darfst nicht ein oder mehrere Figuren des Gegners ununterbrochen bedrohen ohne zu schlagen."

Here, "schlagen" literally means "beating" in the sense of "attacking" but not "beating" in the sense of "defeating". So the message means that you cannot chase indefinitely without attacking (in proper ISF parlor). At best, this message is incomplete since you can also stop chasing as you point out. 

The use of "beat" is interesting because it's the same word Herr Krap used with myself and The Prof to explain why a scout could not threaten a Marshal...it could not "beat" it, which is pretty much what you call utter nonsense. Just because a piece is inferior does not mean it can't threaten a superior piece and therefore even chase a piece. Who among us hasn't chased a known Colonel or General with an unknown but inferior piece? Besides, with an inferior piece the goal is often not to capture/"beat" but merely to gain information on an unknown piece. Whether a chasing piece is superior is irrelevant to the fact of whether it can chase another piece.

 

The Gravon programming does not consider ranks during the chasing. I posted an example in the Quiz and Training thread of a scout and a spy continuously chasing a scout, and here Gravon correctly forbade the spy from threatening into a repeated position.

When I get back home from traveling Monday and on a desktop I'm going to post my poll on scout movement. It's a subject that, again, Gravon had programmed wrong when we checked, and likely still does. Believe it or not, this site has the correct programming with regards to scout movement rules and Gravon wrong.

 

As I see it, the ISF-rule concerning continuous chasing is currently ambiguous about the following:

 

1) how many moves does it require to continuously chase? Chase at least 2 moves in a row, or at least 3 moves in a row? The phrase "more-squares rule" as opposed to "two-squares rule" suggests the latter, but Gravon adheres to the former: the scout vs scout/spy example here features a chase over only two squares, and similarly in the Quiz and Training thread.

2) is the history being reset after a chasing sequence is interrupted? On Gravon it is not, but Nortrom/The Prof and all computer programs (including the one by Vincent de Boer) do reset the list of repeated positions.

 

If it is true that the man behind Gravon (you mentioned Dieter Krapp) is also an ISF member, then I suggest the ISF has a discussion about how referees should rule the examples posted here. It would be rather bad if in a future game Nortrom-Krapp such a position were to come on the board :)


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#15 Don_Homer

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Posted 24 September 2018 - 11:07 AM

Interesting findings, Templaterex! Great efforts. I always thought gravon was (near) perfect in square rules. Still its close to it anyway :)


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#16 GaryLShelton

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Posted 24 September 2018 - 06:12 PM

At Gravon the programming would evidently have given the game to Enigma and for the total game memory as opposed to just the current chasing sequence as you state, though that's awfully quick to block in my mind.

I personally would find this an incorrect programming as well.

For what it's worth, all the computer programs at the 2008-2010 world computer championships reset the memory buffer as soon as a chasing sequence is being broken. I am also sympathetic to this interpretation, but I think the ISF rule as it stand is ambiguous about it..

The ISF is indeed vague about the question, I will agree. The Prof and I had to inquire about that as well. And to be honest, I can't recall Herr Krapp's response. But if you think about it, no arbiter could monitor multiple games and possibly know if any board position were repeated earlier in all of them. Repeated position would have to be what could be readily assessed. That seems logical, at least.

We definitely clarified this in our SMT proposal.


Just to highlight it, and to repeat something The Prof stated at that link above, no piece is chased unless it evades immediately after the threatening piece moves into a full-bind with it. So if a piece does not evade, it is not being chased, as is the case with some of the scouts in the four scout example.

If you threaten multiple pieces (as red does in this example), only one piece can evade of course. And indeed, after every threatening move by red, blue evades at least one piece. Only if red would have captured the non-evading piece, then the chasing sequence would have been broken. I hope we can all agree on that?.

That only one piece can evade does not alter the fact that the other pieces being threatened do not evade. Because they do not evade these pieces cannot be counted as being chased. The definition of chasing requires evasion. Below I reprint the ISF rules on the matter.


11.3
Definitions:
continuous chase: the same player is non-stop threatening one or more pieces of his opponent that is/are evading the threatening moves.
chasing move: a move in a continuous chase that threatens an opponent's piece that was evading during the continuous chase.



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The complete GS&F Rules can be found here: http://forum.strateg...rum-rules-2016/

Draw Refusal Rules, specifically, can be read here: http://forum.strateg...931#entry468931


#17 GaryLShelton

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Posted 24 September 2018 - 07:49 PM

How FEW chasing moves it takes before blocking is a good question. It will depend on heavily on whether it's only the current chase sequence that's remembered, or the full game.

Conversely, how MANY chasing moves could occur before blocking is another good question. It could technically take a long time (under RBP) if the chased piece evades to new squares completely across the board. For example, assume we have a red captain on I1 and a blue lieut on J2, and it's red's turn to move. The chasing then begins up the I and J line.

Red to I2 (1st chasing move), Blue to J3
Red to I3 (2nd chasing move), Blue to J4
Etc., Etc., Etc.

In this sequence Blue evades straight across the board to J10. And Red makes his 9th chasing move to I10 right after. Once Blue moves back to J9, Red will be blocked from moving back to I9 because of repeated board position.*

Obviously, blocking could be much sooner. It totally depends on which way the evading piece moves. In a typical chase ranging over three squares, RBP blocking will happen on the 5th chasing move in that case.

* Would an ISF arbiter allow this? Technically he should but maybe someone with ISF experience could say.

i77rs4m.jpg

The complete GS&F Rules can be found here: http://forum.strateg...rum-rules-2016/

Draw Refusal Rules, specifically, can be read here: http://forum.strateg...931#entry468931





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