Allowing suicide

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Sébastien Dauby

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Apr 29, 1998, 3:00:00 AM4/29/98
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Hello all,

I have read on Robert Jasiek's page that some rule sets allow suicide. I
have wondered what are the consequences of allowing suicide and all I've
come up with is that it allows more ko threats, as in :

.OXXXXO
OXX...O
XXOOOOO
OOO....

where O can use suicide in the upper left corner to create a threat which
would otherwise not exist. Am I missing more subtle consequences ?

Another question I have been unable to answer is whether it is more
satisfying from a theoretical point of view to allow or to forbid suicide.

Thanks for any comments.

sd.

peter zandveld

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Apr 29, 1998, 3:00:00 AM4/29/98
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At least one position has been created by Ger Hungerink where it actually
makes a difference in a capturing race. Sorry I could not find the diagram.
It has been published in the dutch go journal 10-15 years ago.


--
Peter Zandveld
Schaak en go winkel het Paard
Specialist shop for Go, chess, bridge.....
Pa...@xs4all.nl
http://www.xs4all.nl/~paard

Sébastien Dauby <Sebasti...@polytechnique.fr> schreef in artikel
<6i5r9t$m...@polytechnique.polytechnique.fr>...

Nick Wedd

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Apr 29, 1998, 3:00:00 AM4/29/98
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In article <6i5r9t$m...@polytechnique.polytechnique.fr>, Sébastien Dauby
<Sebasti...@polytechnique.fr> writes

>I have read on Robert Jasiek's page that some rule sets allow suicide. I
>have wondered what are the consequences of allowing suicide and all I've
>come up with is that it allows more ko threats, as in :
>
>.OXXXXO
>OXX...O
>XXOOOOO
>OOO....
>
>where O can use suicide in the upper left corner to create a threat which
>would otherwise not exist. Am I missing more subtle consequences ?

Yes. Here are two very improbable positions where suicide is a good move,
both from Harry Fernley's bestiary of remarkable positions:

http://www.eng.ox.ac.uk/people/Harry.Fearnley/go/bestiary/various.new.html
http://www.eng.ox.ac.uk/people/Harry.Fearnley/go/bestiary/nsw2.beast

>Another question I have been unable to answer is whether it is more
>satisfying from a theoretical point of view to allow or to forbid suicide.

Nick
--
Nick Wedd ni...@maproom.demon.co.uk

Robert Jasiek

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Apr 29, 1998, 3:00:00 AM4/29/98
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> have wondered what are the consequences of allowing suicide and all I've
> come up with is that it allows more ko threats, as in :

It also makes a difference in arcane semeais:

O O O O O . .
X X X X O . .
. . . X O . .
O O O X O O O
X . O X X X O
X X O X . X O

And in theoretical studies suicide makes things more complex.

> Another question I have been unable to answer is whether it is more
> satisfying from a theoretical point of view to allow or to forbid suicide.

Once one has first defined intentions for a rule set, one can
deduce satifying views. Ie there are pros and cons. Eg pro: more
variation, con: no "bad" interpretational feeling.

My opinion: suicide is a move on an empty point like any other move
on an empty point. Just the consequences are different. It is not
too far fetched to call the following a suicuide as well:

. . . .
O X X .
. O O X
O X X .
. . . .

X to play:

. . . .
O X X .
X O O X
O X X .
. . . .

Only the consequences of the move gain liberties. One might as well
rule to remove own stones w/o liberty first. Preferring the other
choice is tradition and has become familiar to us. If one prefers
more variation due to removal of opposing stones first, it is
natural to add even more variation by allowing suicide. After all,
suicide is just a name which creates bad feelings here. One could
have termed this "ingenious sacrifice"!

--
robert jasiek
http://www.snafu.de/~jasiek/rules.html


Steve Bailey

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Apr 29, 1998, 3:00:00 AM4/29/98
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Sébastien Dauby <Sebasti...@polytechnique.fr> wrote in article
<6i5r9t$m...@polytechnique.polytechnique.fr>...
> Hello all,

>
> I have read on Robert Jasiek's page that some rule sets allow suicide. I
> have wondered what are the consequences of allowing suicide and all I've
> come up with is that it allows more ko threats, as in :
>
> .OXXXXO
> OXX...O
> XXOOOOO
> OOO....
>
> where O can use suicide in the upper left corner to create a threat which
> would otherwise not exist. Am I missing more subtle consequences ?
>
> Another question I have been unable to answer is whether it is more
> satisfying from a theoretical point of view to allow or to forbid
suicide.
>

I don't KNOW of any other possibilities though I believe that there are
some.

I think permitting suicide leads to mathematically cleaner rules, though I
have no reasoning behind this statement.

=== Steve Bailey s...@zed-inst.co.uk

John Tromp

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Apr 29, 1998, 3:00:00 AM4/29/98
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"Steve Bailey" <s...@zed-inst.co.uk> writes:

>> Another question I have been unable to answer is whether it is more
>> satisfying from a theoretical point of view to allow or to forbid
>suicide.

>I think permitting suicide leads to mathematically cleaner rules, though I
>have no reasoning behind this statement.

Suicide allows an unconditional statement of what a move is:

A move consists of placing a stone on an empty point,
then removing the opponent libertyless stones,
and then removing one's own libertyless stones.

The 2nd "then" above is meant to imply that one reconsiders liberties
in view of any removed stones.

Without suicide, one first explains what a move does, and then adds
an extra condition:

A move consists of placing a stone on an empty point,
and then removing the opponent libertyless stones,
provided this leaves one's own stones with liberties.

A less desirable approach is to first define what a move is as in
the first 2 lines, and then as a separate rule say that some moves are
illegal. In this case particularly, the lack of motivation of the illegality
of certain moves is disturbing. Certainly, suicide moves are almost
invariably pointless, but that hardly merits forbidding them. Go is a game
of skill after all, so players don't need to be told what's bad for them.

Allowing suicide also has the nice property that ko becomes the ONLY
reason for a move being illegal.

The only good reason I could think of for forbidding suicide is that it
would not be clear what the result of such a move should be, but that is
not the case either.

As Robert Jasiek pointed out, it is unfortunate that the word chosen for
this phenomenon has such bad connotations...

regards,


%!PS % -John Tromp (http://www.cwi.nl/~tromp/)
42 42 scale 7 9 translate .07 setlinewidth .5 setgray/c{arc clip fill
setgray}def 1 0 0 42 1 0 c 0 1 1{0 3 3 90 270 arc 0 0 6 0 -3 3 90 270
arcn 270 90 c -2 2 4{-6 moveto 0 12 rlineto}for -5 2 5{-3 exch moveto
9 0 rlineto}for stroke 0 0 3 1 1 0 c 180 rotate initclip}for showpage

Robert Jasiek

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Apr 29, 1998, 3:00:00 AM4/29/98
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> I think permitting suicide leads to mathematically cleaner rules, though I
> have no reasoning behind this statement.

A) Probably, you think of the stages of a move with allowed suicide:
1) put a stone on empty point of board,
2) possibly execute consequences of this putting.

B) Without suicide:
1) restrict the set of valid empty points of the board to disenable
suicide,
2) put a stone on a valid empty point of the board,
3) possibly execute consequences of this putting.

(A2) contains opposing surrounded stones , then own surrounded stones;
this is also part of (B1), so that (B3) can be restricted to opposing
stones.

Altogether, (A) is simpler than (B). Maybe this is the kind of thing
you call "mathematically cleaner".

Robert Jasiek

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Apr 29, 1998, 3:00:00 AM4/29/98
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> A move consists of placing a stone on an empty point,
> and then removing the opponent libertyless stones,
> provided this leaves one's own stones with liberties.

This short formulation is hard to understand correctly for beginners,
IMHO.
(Does "provided" restrict "removing" or this togther with "a move
consists"
and if so, is it possible that a move does not exist at all then...?)

> Allowing suicide also has the nice property that ko becomes the ONLY
> reason for a move being illegal.

Agreed in principle. However, most ko rules do not prevent extremely
long games. Thus, in practice, one needs further prohibitions as to
the game end, e.g. a constant game end rule. Or one would have to
disturb
the game's common nature by letting all kos be disturbing kos or
applying
primitive prohibition rules or the like. (Even Japanese voidness does
not
prevent long cycles from occuring at least once.)

--
robert jasiek
http://www.snafu.de/~jasiek/


Barry Phease

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Apr 30, 1998, 3:00:00 AM4/30/98
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Sébastien Dauby wrote:

> Another question I have been unable to answer is whether it is more
> satisfying from a theoretical point of view to allow or to forbid suicide.
>

> Thanks for any comments.

When we were drafting the NZ rules we considered the question. We wrote
the rules with suicide forbidden and then decided they would look better
if it wasn't. It is the same reason we excluded fixed handicap stones.
We applied the go proverb "An unnecessary move is a bad move" and
replaced the word "move" with "rule".

Allowing suicide gives more scope for showing skill (or lack of it).
With beginners it is a good idea to allow them to retract suicide moves.

--
Barry Phease

mailto:bar...@es.co.nz
http://www.es.co.nz/~barryp

dmori...@hotmail.com

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Apr 30, 1998, 3:00:00 AM4/30/98
to

In article <6i5r9t$m...@polytechnique.polytechnique.fr>,

"Sébastien Dauby" <Sebasti...@polytechnique.fr> wrote:
>
> Hello all,
>
> I have read on Robert Jasiek's page that some rule sets allow suicide. I
> have wondered what are the consequences of allowing suicide and all I've
> come up with is that it allows more ko threats, as in :
>
> .OXXXXO
> OXX...O
> XXOOOOO
> OOO....
>
> where O can use suicide in the upper left corner to create a threat which
> would otherwise not exist. Am I missing more subtle consequences ?
>
> Another question I have been unable to answer is whether it is more
> satisfying from a theoretical point of view to allow or to forbid suicide.
>
> Thanks for any comments.
>
> sd.
>
>I don't think that it will prevent people from killing themselves if we make
the suicide illegal. Denis.


-----== Posted via Deja News, The Leader in Internet Discussion ==-----
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Bill Taylor

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May 5, 1998, 3:00:00 AM5/5/98
to

WARNING: This post may contain remarks that might be construed as offensive
======= to certain groups of people. If you feel you may be offended by
reading remarks of such a type - PLEASE DO NOT READ THIS ARTICLE.
-------------------------------------------===============================

Doubtless this warning still won't assuage the ravening hoards of
howler monkeys that infest this group... Still, one does what one can.


Robert Jasiek writes:

>After all, suicide is just a name which creates bad feelings here.

Good point. The oddest thing about this, though, I've always thought,
is that it is in christian and post-christian countries, where suicide
is thought to be an unequivocally "bad thing". In non-Judeao-descended
cultures it's usually been thought as fair enough. And this was seemingly
never more so than in pre-Meiji Japan, where it was not only OK but in
fact substantially honorable. And yet, it is in Japan that the strongest
opposition to "suicide moves" exists, seemingly. Odd. Maybe the name
for suicide moves in Japanese is something not involving the terms seppuku
or hara-kiri. Can any Japanese-speaking gothusiasts inform us here?

> One could have termed this "ingenious sacrifice"!

Yes. Nicely put.

---------------------

Barry Phease writes:

>It is the same reason we excluded fixed handicap stones.
>We applied the go proverb "An unnecessary move is a bad move" and
>replaced the word "move" with "rule".

Yes, an excellent precept, both ways. (Provided of course it leaves the
game substantially unaltered, as is the case here.)

A very sensible pragmatic Kiwi approach to things.
What a pity it isn't adopted in... uh... elsewhere.


>Allowing suicide gives more scope for showing skill (or lack of it).

Yes, good point.

>With beginners it is a good idea to allow them to retract suicide moves.

Yes, fair enough; as with other types of basic blunder.

Interestingly, when suicide comes up, (only with beginners, in practice),
there is an awkward hiatus, where (with or without commentary), one must
*first* pick up some prisoners, and *then* make a move, (and possibly
remove some more prisoners). It seems "unnatural", "the wrong way round".

This leads me to consider the following slight rule variant with a more
natural "flow" of move action.

================
If a (say) black move leaves black with a libertyless group, the stones
are LEFT on the board briefly, until white has made his move, and THEN
all subsequent black prisoners are removed.
================

This would have the effect of forbidding an immediate placement
"under the stones", as it were. So a position like this one...

__________________
|. X O . X . . . .
|X O O . X . . .
|O O . X . . .
|. . X . . .
|X X X . .
|. . . .
|. .

...leaves black not only with a mere ko-threat in the corner, but with
a valuable move:- If he suicides three stones in the corner, white could
not immediately replay on the corner point, as the stones would remain on
the board for half a move more. Thus white would have to play HIS OWN
threat, a not-ko threat, before his killing placement in the corner.

It seems to me, that as well as being more natural in terms of move flow,
this variant allows still more skill and judgement, in these rare situations.


Hence, I enjoin the go world to consoder it as a useful suicde variant!


----------- ______________________________________________ -----------
| * * * | Bill Taylor W.Ta...@math.canterbury.ac.nz | * * |
| | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | * * |
| * * * | ============================ | * |
| | FREE THE HANDICAP NINE !! | * |
| * * * | ============================ | * * * |
----------- -----------

Tom Hoeber

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May 5, 1998, 3:00:00 AM5/5/98
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Bill Taylor wrote:
>
> Doubtless this warning still won't assuage the ravening hoards of
> howler monkeys that infest this group...
>
Oh no, he's back with his pathetic insults flying. For any newcomers
who are not familiar with Taylor's lurid history, the article
"nosmoke.txt" found at ftp://ftp.nuri.net/Go/articles/nosmoke.txt will
prove illuminating.

Tom Hoeber

Clive Hunt

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May 5, 1998, 3:00:00 AM5/5/98
to

(This posting may be superfluous as I have missed the last couple of weeks)

Has anyone mentioned that there are positions (other than mere use as ko
threats) where suicide is the desired move i.e. the only way to win the
local semiai? In such a case, the prohibition of the suicide move causes a
substantial change to the nature of the game (well, in rare positions).

I guess quite a few dan players don't know this and would find it an
interesting challenge to construct an example of the abovementioned
situation (I only know from being shown).

Clive Hunt
Johannesburg

Robert Jasiek

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May 5, 1998, 3:00:00 AM5/5/98
to

> Has anyone mentioned that there are positions (other than mere use as ko
> threats) where suicide is the desired move i.e. the only way to win the
> local semiai?
> interesting challenge to construct an example of the abovementioned
> situation

Even more challenging: find applications other than either ko threat
or local semeai.

shu...@itsa.ucsf.edu

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May 5, 1998, 3:00:00 AM5/5/98
to

>One thing I will say for your postings: they make even Sam Sloan look
>like a constructive contributor to this newsgroup, by comparison.

I guess Nick is interested in Sam Sloan's penis too.


Nick Wedd

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May 6, 1998, 3:00:00 AM5/6/98
to

In article <354F58...@chatlink.com>, Tom Hoeber
<will...@chatlink.com> writes

>Oh no, he's back with his pathetic insults flying.

Back? He's been here all along, and unlike you, he is interested in Go.

One thing I will say for your postings: they make even Sam Sloan look
like a constructive contributor to this newsgroup, by comparison.

Nick
--
Nick Wedd ni...@maproom.demon.co.uk

Tim Tyler

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May 6, 1998, 3:00:00 AM5/6/98
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Bill Taylor (mat...@math.canterbury.ac.nz) wrote:

[snip]

: Interestingly, when suicide comes up, (only with beginners, in practice),


: there is an awkward hiatus, where (with or without commentary), one must
: *first* pick up some prisoners, and *then* make a move, (and possibly
: remove some more prisoners). It seems "unnatural", "the wrong way round".

: This leads me to consider the following slight rule variant with a more
: natural "flow" of move action.

: ================
: If a (say) black move leaves black with a libertyless group, the stones
: are LEFT on the board briefly, until white has made his move, and THEN
: all subsequent black prisoners are removed.
: ================

: This would have the effect of forbidding an immediate placement
: "under the stones", as it were. So a position like this one...

: __________________
: |. X O . X . . . .
: |X O O . X . . .
: |O O . X . . .
: |. . X . . .
: |X X X . .
: |. . . .

: ...leaves black not only with a mere ko-threat in the corner, but with


: a valuable move:- If he suicides three stones in the corner, white could
: not immediately replay on the corner point, as the stones would remain on
: the board for half a move more. Thus white would have to play HIS OWN
: threat, a not-ko threat, before his killing placement in the corner.

: It seems to me, that as well as being more natural in terms of move flow,
: this variant allows still more skill and judgement, in these rare situations.

: Hence, I enjoin the go world to consoder it as a useful suicde variant!

Interesting.

I'm not sure what I make of the notion of the move-flow being more natural.
I like legal suicide, but have though that the stones should be removed from
the board and offered to the opponent by the player who performs the suicidal
move.

Bill's variant does indeed introduce additional interesting complications.

However, I'm not sure what I make of it on aesthetic grounds.
--
__________
|im |yler The Mandala Centre http://www.mandala.co.uk t...@cryogen.com

Bob Hearn

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May 6, 1998, 3:00:00 AM5/6/98
to

> Bill Taylor (mat...@math.canterbury.ac.nz) wrote:
>
> [snip]
>

> : This leads me to consider the following slight rule variant with a more
> : natural "flow" of move action.
>
> : ================
> : If a (say) black move leaves black with a libertyless group, the stones
> : are LEFT on the board briefly, until white has made his move, and THEN
> : all subsequent black prisoners are removed.
> : ================
>
> : This would have the effect of forbidding an immediate placement
> : "under the stones", as it were.
>

> [snip]


> : Hence, I enjoin the go world to consoder it as a useful suicde variant!
>
> Interesting.
>
> I'm not sure what I make of the notion of the move-flow being more natural.
> I like legal suicide, but have though that the stones should be removed from
> the board and offered to the opponent by the player who performs the suicidal
> move.
>
> Bill's variant does indeed introduce additional interesting complications.
>
> However, I'm not sure what I make of it on aesthetic grounds.

Well, it does lead to a simpler formulation of the rules, I think:

"A move consists of a player placing a stone on an unoccupied intersection,
then removing all libertyless groups of stones of the opposing color."

In that sense, it wins on aesthetics. It does change the game quite a bit,
though. The next logical step in this direction would be the rule:

"A move consists of a player placing a stone on an unoccupied intersection,
then removing all libertyless groups of stones."

This would of course change capturing significantly! In particular, it
would add a third possibility to the result of a ko fight, stalemate:

......
..xo..
.xxoo.
..xo..
......


Bob Hearn
b...@gobe.com

Nick Wedd

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May 7, 1998, 3:00:00 AM5/7/98
to

In article <354F84...@berlin.snafu.de>, Robert Jasiek
<jas...@berlin.snafu.de> writes

>> Has anyone mentioned that there are positions (other than mere use as ko
>> threats) where suicide is the desired move i.e. the only way to win the
>> local semiai?
>> interesting challenge to construct an example of the abovementioned
>> situation
>
>Even more challenging: find applications other than either ko threat
>or local semeai.

Look at
http://www.eng.ox.ac.uk/people/Harry.Fearnley/go/bestiary/nsw2.beast

I would not call this a semeai, or a capturing race. It is just a
status problem for the black group, which has ample outside liberties.

I have posted it here before, a couple of years ago, but here it is
again (lower edge):

. . . . . . . . . . . . . . . . . . .
. . . . . . . O O O O O O . . . . . .
. . . , . . O . . , . . . O . , . . .
. . O O O . O X X X X X X O . O O O .
. O . . . . O X . O O O X O . . . . .
. . X X X X X O O X . O O X X X X X .

^ ^
b a

As things stand, if suicide is forbidden, X is dead. O eventually fills
all the outside liberties, and when X captures two stones, O throws in
at b.

If suicide is allowed, X plays at a, and is alive.

This position is from the Journal of the European Go Congress, 1987.

Joe M. McClendon

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May 7, 1998, 3:00:00 AM5/7/98
to

Nick Wedd wrote on May 6, 1998:

>
> In article <354F58...@chatlink.com>, Tom Hoeber
> <will...@chatlink.com> writes
>
>> Oh no, he's back with his pathetic insults flying.
>
> Back? He's been here all along, and unlike you, he is interested
> in Go.
>
> One thing I will say for your postings: they make even Sam Sloan
> look like a constructive contributor to this newsgroup, by
> comparison.
>
> Nick
> --
> Nick Wedd ni...@maproom.demon.co.uk


Hmmmm ??? I see Nick, you are trying to tell us that you feel
that anyone who posts articles criticizing Bill Taylor can not
possibly be interested in the game of Go. Nick, surely you need
to think about this much more carefully.

Also Nick, surely you need to think much more carefully about the
very pitiful wisdom of comparing Sam Sloan to anyone in any kind
of derogatory article that you post to rec.games.go, especially at
a time when several previous articles had recently been posted with
comments about photos of Sam Sloan's genitalia. It seems Nick, that
by failing to think carefully about this, you have unwittingly made
yourself vulnerable to articles by others with some very predictable
ridicule. Some would say "well justified ridicule". Indeed, one
such article has already been posted. Just think about this Nick.
In a very awkward and unjustified attempt to ridicule Tom Hoeber,
you have posted a derogatory article that associates in that same
article the name "Nick Wedd" with the name "Sam Sloan", at a time
when many readers of this newsgroup associate the name "Sam Sloan"
with recent comments about photos of his genitalia. Now, with
a name like "Nick Wedd", it is not difficult to imagine how your
name may be accidentally misspelled in some articles posted to
this newsgroup in the future. A pity! So sad!

Many readers of this newsgroup will probably remember Nick, that
Tom Hoeber posted an article several weeks ago to complain about
unsolicited e-mail that you and a few others had been sending to
him. His article was posted on April 2, 1998 and it was titled:
"A Modest Request". In that article, Tom Hoeber made a very
reasonable complaint about the unsolicited e-mail. Nick, some
readers will now feel that the real reason why you posted your
May 6, 1998 article was because it is part of some kind of
vengeance for Tom Hoeber's previous criticism of your unsolicited
e-mail. What a mess! Just for a little revenge!

One possible way out of this Nick, is a timely, sincere, meaningful
and public apology. Sure, it huts to do that, but it can hurt a
lot more for a much longer time if you fail to do it. But remember,
Bill Taylor and his apologists may feel that your May 6, 1998
article reveals that you have climbed down from your semi-neutral
fence and are running toward their racist camp. So, of course,
they may be very likely to try to encourage you to continue running
in their direction.

Nick, before you run any further in any direction, I recommend that
you read once again the very excellent and very charitable article
that Dave Marvit posted to this newsgroup on April 18, 1998, titled:
"Making Explicit Bill Taylor's Racism". I also recommend that
article for others, even if they are not runners.

Joe

--
Joe M. McClendon - joeg...@worldnet.att.net - hamaki on IGS
--
- "Journalists come down from the safety of the hills after
the battle and shoot the wounded." - The late Robert C.
Maynard, former editor and publisher, Oakland Tribune.

Bill Taylor

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May 8, 1998, 3:00:00 AM5/8/98
to

b...@gobe.com (Bob Hearn) writes:

|> Well, it does lead to a simpler formulation of the rules, I think:
|>
|> "A move consists of a player placing a stone on an unoccupied intersection,
|> then removing all libertyless groups of stones of the opposing color."

Yes, very true, good point. Neat; and no reference to suicide is made at
all, not even an implied one (as at present).


Not to be taken seriously - but another advantage of the new suicide rule
would be to temperature-sensing micro-go-scopists, (hi Bill, John & Ted),
[pronounced microGOScopists]. At present 2x2 and similar games are boring
or nasty to analyse in terms of temperature, as e.g. X . X . X .
are all in a nasty loop leading to boring 0-scores. X . X O X X

However, with the new suicide rule, as written above, the third one can
lead to an immediate win for black! If he fills the last point, his 4
stones stay on, white has no place to play so must PASS! Then black can
pass and the game stops at 4 points to black!! Howbout that!? And one
could even claim some naturalness, as this board X X
hardly seems a capture to white, with no stones X X
white's in contact with any of black's. :-)

However, that is a mere jokey aside. The real bonus would be the extra skill
available in the rare positions such as I mentioned before.


|> It does change the game quite a bit, though.

Eh? I don't follow. If you mean change those positions such as I mentioned,
well, the ordinary suicide rule (e.g. Ing, NZ) already changes it from the
no-suicide (NK, AGA) rule. But it can hardly be called a BIG change when
it would be so rare anyway. And not SO big even then.


|> The next logical step in this direction would be the rule:
|>
|> "A move consists of a player placing a stone on an unoccupied intersection,
|> then removing all libertyless groups of stones."

Yes, John Tromp wrote an article on that a year or so ago. There were
some interesting considerations involved. In particular, with simple kos
(using the superko rule) the *other* person has to find the first ko-threat!

The game was changed less than one might expect, but was noticeably not like
current go in some respects.

-------------------------------------------------------------------------------
Bill Taylor W.Ta...@math.canterbury.ac.nz
-------------------------------------------------------------------------------
"Do not pass" GO = do not collect $200.
-------------------------------------------------------------------------------

P.S. To the net-cops, lest they feel forgotten. :)

Hi Tom, Joe, shudi, how's tricks? Still reading articles you've
been specifically warned against, I see! ;-) That's the ticket;
don't you let anything through the net! Cor; you might be sacked...

Bob Hearn

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May 8, 1998, 3:00:00 AM5/8/98
to

In article <6iu98t$sfo$1...@cantuc.canterbury.ac.nz>,
mat...@math.canterbury.ac.nz (Bill Taylor) wrote:

> b...@gobe.com (Bob Hearn) writes:
>
> |> Well, it does lead to a simpler formulation of the rules, I think:
> |>
> |> "A move consists of a player placing a stone on an unoccupied intersection,
> |> then removing all libertyless groups of stones of the opposing color."
>
> Yes, very true, good point. Neat; and no reference to suicide is made at
> all, not even an implied one (as at present).
>

> |> It does change the game quite a bit, though.
>
> Eh? I don't follow. If you mean change those positions such as I mentioned,
> well, the ordinary suicide rule (e.g. Ing, NZ) already changes it from the
> no-suicide (NK, AGA) rule. But it can hardly be called a BIG change when
> it would be so rare anyway. And not SO big even then.

Well, apart from the extremely obscure cases, the only practical effect
of allowing suicides is to make some oshitsubushi patterns into ko threats:

__________________
|. X O . X . . . .
|X O O . X . . .
|O O . X . . .
|. . X . . .
|X X X . .

These are reasonably common patterns, by the way, not really rare. But
making them ko threats is not a huge change. Your change goes a step beyond
this, creating a fundamentally new kind of position that is sort of like a
ko, in that if black plays in the corner, white has to make a threat:
a "not-ko" threat, as you call it. This is interesting, but undeniably
different from existing go.

The effect of allowing suicide in this position I would call more quantitative,
in that it creates one more ko threat for black; but your change makes this
a qualitatively new kind of position, I think.

Bob Hearn
b...@gobe.com

Tim Casey

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May 8, 1998, 3:00:00 AM5/8/98
to

From: Jeff.B...@bbs.bragg.army.mil
Date: 8 May 1998 20:27:44 EDT
Subject: please post to r.g.g. :-)

> From: mat...@math.canterbury.ac.nz (Bill Taylor)
> Newsgroups: rec.games.go
> Subject: Re: Allowing suicide
> Date: 8 May 1998 06:38:21 GMT

> b...@gobe.com (Bob Hearn) writes:

> |> Well, it does lead to a simpler formulation of the rules, I think:
> |>
> |> "A move consists of a player placing a stone on an unoccupied intersection
,
> |> then removing all libertyless groups of stones of the opposing color."

> Yes, very true, good point. Neat; and no reference to suicide is made at
> all, not even an implied one (as at present).

Nope. Simpler to say: "a move consists of a player placing a stone
on an unoccupied intersection, then removing all libertyless groups."

In that way, the 'suicide' move reduces to pass.


> P.S. To the net-cops, lest they feel forgotten.

We're not here to put you away, just make arrests. :-)

- regards
- jb

D & A Klinkenberg

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May 9, 1998, 3:00:00 AM5/9/98
to

Tim Casey wrote:
> From: Jeff.B...@bbs.bragg.army.mil
[snip]
> > From: mat...@math.canterbury.ac.nz (Bill Taylor)
[snip]
> > b...@gobe.com (Bob Hearn) writes:
[snip]

> Nope. Simpler to say: "a move consists of a player placing a stone
> on an unoccupied intersection, then removing all libertyless groups."
> In that way, the 'suicide' move reduces to pass.
[snip]
> - regards
> - jb
###
Hello Tim and rrg readers,
If I understand the things quoted above, I disagree. I have been
following this subject with interest, but I did not follow who the writers
have been. I am sorry, but I don't really don't know who wrote the things
quoted above.
I think that if a suicide move is permitted and made, that the other
player should be allowed to remove that stone (and any stones which
'connect' to it) before he makes his play. Then the suicide move could be
used as a ko threat.
As a rule it might state that if, when your turn starts, there is a
group of (one or more) of the opponent's stones with no liberties, that
group may (must?) be removed BEFORE you make your move.
Suppose that the group with no liberties has three stones. It may well
be critical to know who has the first chance to play a stone in the space
that remains after those three stones are removed.
Dan who plays go in Woodstock, NY and Albany, NY.

Tim Casey

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May 9, 1998, 3:00:00 AM5/9/98
to

From: Jeff.B...@bbs.bragg.army.mil
Date: 9 May 1998 21:07:12 EDT
Subject: handling 'suicide' moves in Go: may post to rgg -

> From: D & A Klinkenberg <klin...@ulster.net>
> Newsgroups: rec.games.go
> Subject: Re: Allowing suicide

> Date: Sat, 09 May 1998 13:49:34 -0400

>> Simpler to say: "a move consists of a player placing a stone
>> on an unoccupied intersection, then removing all libertyless
>> groups." In that way, the 'suicide' move reduces to pass.

> I think that if a suicide move is permitted and made, that the


> other player should be allowed to remove that stone (and any
> stones which 'connect' to it) before he makes his play. Then the
> suicide move could be used as a ko threat.

Yes indeed. Then again, pass-pass also ends play at any time;
if the ko-threat affects game outcome the second player could
instead opt for terminating the game with consecutive pass. Due
to the consecutive pass rule not all 'games' of Go are guaranteed
a score, of course. If they change their mind again and wish to
'resume' play on the position the initial condition of Go applies,
since it is a derivative consequence of opening play that no 'ko'
can be ever captured in the first two moves of a game and both
players must agree who is to move first.

Let's utilize your concept however, to illustrate how BT's 'rule'
for moves in Go can be stated more simply that what he claims:

'The player to move may remove all or any part of libertyless
groups while placing a stone on an unoccupied intersection.'

Seems fair enough. Thanks for providing me with an opportunity
to refine this definition.


- regards
- jb

.


Bob Hearn

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May 11, 1998, 3:00:00 AM5/11/98
to

In article <6j8mhi$t3k$1...@cantuc.canterbury.ac.nz>,
mat...@math.canterbury.ac.nz (Bill Taylor) wrote:

> b...@gobe.com (Bob Hearn) writes:
>

[ Re: "A move consists of a player placing a stone on an unoccupied
intersection, then removing all libertyless groups of stones of
the opposing color." ]

> |> __________________
> |> |. X O . X . . . .
> |> |X O O . X . . .
> |> |O O . X . . .
> |> |. . X . . .
> |> |X X X . .
> |>

> |> The effect of allowing suicide in this position I would call more
quantitative,
> |> in that it creates one more ko threat for black; but your change makes this
> |> a qualitatively new kind of position, I think.
>

> Interesting terminology. Nice.
>
> All things considered, I think you're right. Pity. It was a cute idea.

Yes... I'm all for the simplest rules possible, on aesthetic grounds.
I don't think this rule is so way out that it would be inappropriate for
XYZ Official Rules. It's just that it would change the game.

The other thing about it is that perhaps it is against the spirit of go
for there ever to be a state in which a libertyless group is left on the
board.

Bob

Bill Taylor

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May 12, 1998, 3:00:00 AM5/12/98
to

b...@gobe.com (Bob Hearn) writes:

|> __________________
|> |. X O . X . . . .
|> |X O O . X . . .
|> |O O . X . . .
|> |. . X . . .
|> |X X X . .
|>

|> making them ko threats is not a huge change. Your change goes a step beyond
|> this, creating a fundamentally new kind of position that is sort of like a
|> ko, in that if black plays in the corner, white has to make a threat:
|> a "not-ko" threat, as you call it. This is interesting, but undeniably
|> different from existing go.

Yes, I must say this is true. You make a good point.


|> The effect of allowing suicide in this position I would call more quantitative,
|> in that it creates one more ko threat for black; but your change makes this
|> a qualitatively new kind of position, I think.

Interesting terminology. Nice.


|> These are reasonably common patterns, by the way, not really rare.

The key point. Certainly they are more common than the usual weirdies
that get into rules debates. They are not so very common, but taking into
account games influenced by the fact that they *could* occur, we might
call them "latent occurences", or "virtual occurrences", then they are
quite common in fact, I agree.

All things considered, I think you're right. Pity. It was a cute idea.

-------------------------------------------------------------------------------
Bill Taylor W.Ta...@math.canterbury.ac.nz
-------------------------------------------------------------------------------
In the land of the blind, the one-eyed group is king!
-------------------------------------------------------------------------------


Andre Engels

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May 13, 1998, 3:00:00 AM5/13/98
to Tim Casey

Tim Casey wrote:

> Nope. Simpler to say: "a move consists of a player placing a stone
> on an unoccupied intersection, then removing all libertyless groups."


>
> In that way, the 'suicide' move reduces to pass.

This proposed rule will not lead to something that I would
recognize as 'normal go', but to 'simultaneous capture'. To
get to normal go, you must specify that "a move consists of

a player placing a stone on an unoccupied intersection, then

removing all libertyless groups of the opponent, then removing
all libertyless groups of his own."


--
Andre Engels, eng...@win.tue.nl, ICQ #6260644
http://www.win.tue.nl/cs/fm/engels/index_en.html

If we know only our own side of the argument, we hardly know even that;
it becomes stale, soon learned only by rote, a pallid and lifeless
truth.
- Ann Druyan

Tim Casey

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May 13, 1998, 3:00:00 AM5/13/98
to

From: Jeff.B...@bbs.bragg.army.mil
Date: 13 May 1998 12:34:50 EDT
Subject: simul-cap not the problem. (post to r.g.g.-thx).

> Subject: Re: Allowing suicide
> From: Andre Engels <eng...@win.tue.nl>
> Date: Wed, 13 May 1998 01:36:36 -0700
> Newsgroups: rec.games.go


> Jeff Boscole wrote:
>> Nope. Simpler to say: "a move consists of a player placing a stone
>> on an unoccupied intersection, then removing all libertyless groups."
>> In that way, the 'suicide' move reduces to pass.

> This proposed rule will not lead to something that I would
> recognize as 'normal go', but to 'simultaneous capture'. To
> get to normal go, you must specify that "a move consists of
> a player placing a stone on an unoccupied intersection, then
> removing all libertyless groups of the opponent, then removing
> all libertyless groups of his own."

Yes, the rule -- stated as simply as possible -- had been revised
after a subsequent posting to r.g.g. to read:

" (e) The player to move -may- remove all or any part of "libertyless
groups" not in "ko" status while placing one stone on any unoccupied
intersection. The player who does removal may keep these stones.
Captured stones of opposite color are called prisoners and cannot be
returned to play. "

I can't see an advantage in why the player would elect to remove
his/her own stones. And then, as a 'suicide' maneuver produces
one "pass" condition (since the heap-total does not increase) the
opponent may elect for second "pass" if there's an undue problem with
'ko-threat' on the board, thereby suspending play. Resumption of play
then requires agreement on who moves first with no ko-capture on the
first two moves, as we find in opening play.

So 'suicide' can be allowed but it doesn't accomplish anything other
then presenting an option of stopping the clock and a temporary
disruption of play. In -this- sense the rules would be 'shifted'
slightly, but the upshot is to make for Go a more courteous activity.


> If we know only our own side of the argument, we hardly know even that;
> it becomes stale, soon learned only by rote, a pallid and lifeless truth.
> - Ann Druyan

Ditto.

Bill Taylor

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May 13, 1998, 3:00:00 AM5/13/98
to

b...@gobe.com (Bob Hearn) writes:

|> [ Re: "A move consists of a player placing a stone on an unoccupied
|> intersection, then removing all libertyless groups of stones of
|> the opposing color." ]

|> > |> __________________
|> > |> |. X O . X . . . .
|> > |> |X O O . X . . .
|> > |> |O O . X . . .
|> > |> |. . X . . .
|> > |> |X X X . .

|> The other thing about it is that perhaps it is against the spirit of go


|> for there ever to be a state in which a libertyless group is left on

Good point. Using "the spirit of the game" in order to determine which
of several alternate rules is nicest, is a good idea. (Contrast this with
using "the spirit of the rules" to leave the rules ambiguous in the pious
hope that they will miraculously be clear, which is quite the opposite,
and a really BIG no-no. Both Ing and J89 do this.)

The spirit of the game also leads us to reject territory scoring in
favour of area scoring. Also to declare stalemate to be a win in chess,
and to remove the offside rule in soccer; all good things to do IMHO.


BTW Bob, in your original post, which alas has gone from here, you called
the above type of position "otsibushi" positions, or something similar.
What *was* the word you used, and what's its literal translation?

-------------------------------------------------------------------------------
Bill Taylor W.Ta...@math.canterbury.ac.nz
-------------------------------------------------------------------------------

Go: It's all fun and games, until someone loses an eye!
-------------------------------------------------------------------------------

Bob Hearn

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May 14, 1998, 3:00:00 AM5/14/98
to

In article <6jbc65$g5f$1...@cantuc.canterbury.ac.nz>,
mat...@math.canterbury.ac.nz (Bill Taylor) wrote:

> b...@gobe.com (Bob Hearn) writes:
>
> |> [ Re: "A move consists of a player placing a stone on an unoccupied
> |> intersection, then removing all libertyless groups of stones of
> |> the opposing color." ]
> |> > |> __________________
> |> > |> |. X O . X . . . .
> |> > |> |X O O . X . . .
> |> > |> |O O . X . . .
> |> > |> |. . X . . .
> |> > |> |X X X . .
>

> The spirit of the game also leads us to reject territory scoring in
> favour of area scoring.

Well, yes, but the results are almost always the same, and as a practical
matter, territory scoring is easier.

> BTW Bob, in your original post, which alas has gone from here, you called
> the above type of position "otsibushi" positions, or something similar.
> What *was* the word you used, and what's its literal translation?

The word is "oshitsubushi." I don't know what the literal translation is.

feld...@bsi.fr

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May 14, 1998, 3:00:00 AM5/14/98
to

In article <6jbc65$g5f$1...@cantuc.canterbury.ac.nz>,
mat...@math.canterbury.ac.nz (Bill Taylor) wrote:
>
> b...@gobe.com (Bob Hearn) writes:
>
> |> [ Re: "A move consists of a player placing a stone on an unoccupied
> |> intersection, then removing all libertyless groups of stones of
> |> the opposing color." ]
> |> > |> __________________
> |> > |> |. X O . X . . . .
> |> > |> |X O O . X . . .
> |> > |> |O O . X . . .
> |> > |> |. . X . . .
> |> > |> |X X X . .
>
> |> The other thing about it is that perhaps it is against the spirit of go
> |> for there ever to be a state in which a libertyless group is left on
>
> Good point. Using "the spirit of the game" in order to determine which
> of several alternate rules is nicest, is a good idea. (Contrast this with
> using "the spirit of the rules" to leave the rules ambiguous in the pious
> hope that they will miraculously be clear, which is quite the opposite,
> and a really BIG no-no. Both Ing and J89 do this.)
>
> The spirit of the game also leads us to reject territory scoring in
> favour of area scoring. Also to declare stalemate to be a win in chess,
> and to remove the offside rule in soccer; all good things to do IMHO.
>

Stalemate decisions (as all rules in chess-type games) are usually made by
*very* strong players, for adding interest to the game (as,for instance,
castling, a move introduced by el Greco around 1630, but still not played in
Italy before 19th century); there is no real "spirit of the game" who can
decide against that. In Go, of course, we have the opposite situation, and in
fact, any clever use of (new) rules changing the status of any group will
usually be rejected for that very reason (see, for instance, what happened to
the "logical" way of counting fractionnal points in seki in the first Ing
rules). On the other hand,what the spirit of the game really is has still
to be decided in a social system with a large consensus: even if you get
convinced that 21 board is better, or that it is more logical to count two
points less for each (living) group, you will simply not be able to convince
the people that count: strong players. I tried, 30 years ago , to introduce
bidding for komi, and was politely but firmly silenced. On the other hand, a
few of my pedagogical innovations are still in use...:)


> BTW Bob, in your original post, which alas has gone from here, you called
> the above type of position "otsibushi" positions, or something similar.
> What *was* the word you used, and what's its literal translation?
>

It is oshi tsubushi : "(ko) crushing"


> -------------------------------------------------------------------------------
> Bill Taylor W.Ta...@math.canterbury.ac.nz
> -------------------------------------------------------------------------------
> Go: It's all fun and games, until someone loses an eye!
> -------------------------------------------------------------------------------
>

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