Reduction

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 4:18 am

When the (bad) proverb says "First reduce, then play on the vital point.", it is weak if the meaning of "reduce" refers to one particular move and place where to reduce. The proverb's meaning is a bit better when "reduce" is understood as a process of reducing the eyespace of an attacked group with several moves from different directions.

Instead of speaking of "a move that reduces the eyespace", several years ago, I have maybe invented the term "reduction". It is a play of the type of reducing the eyespace. With such a term, efficient language use becomes possible, when discussing life and death situations. E.g., "This reduction kills the group."

Similarly, a "connection" used as a type of a move describes a play that connects.

In life and death situations, many reductions are also connections, typically to one's living strings on the outside.

In non-go-English, "reduces by connecting" may sound strange, but for go terms related to life and death situations, it is very efficient use of language.

Efficient terminology is essential for life and death. LD problems can be complicated, and one must not further complicate them by inefficient, clumsy language, such as "the move reduces this connected, visually surrounded part of the board, while ensuring connection of the played stone to other stones. I prefer: "the lake is attacked by the connected reduction". This concentrates on the important contents. Besides, short phrases allow easier descriptions of moves with multiple meanings or threats.

leichtloeslich · Post by **leichtloeslich** » Sat Nov 09, 2013 6:10 am

RJ wrote:The proverb's meaning is a bit better when "reduce" is understood as a process of reducing the eyespace of an attacked group with several moves from different directions.

I would interpret it that way and have problems seeing how anyone could think of "first reduce" to mean "first make a single reduction move" or something similar.
Maybe I would translate it as "Hane, hane, vital point!" or something. Obviously (at least IMHO) the reducing phase is not required to be of a certain length (be it a single move or several moves).

And I don't see how this is a "bad" proverb. It has probably helped more people win games in the last year than all of your research during all of your lifetime combined.

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 6:27 am

It is easy to find examples illustrating why the proverb is bad. E.g., when there is already the one vital point, one must NOT start with a reduction, leaving the vital point to the opponent.

Instead of applying the proverb blindly, think of it as ONE OF SEVERAL POSSIBLY APPLICABLE PROCEDURES. Or embed it in a broader context: If there is an obvious first move, consider it first. Otherwise, consider alternatives, among which the proverb suggests one.

oren · Post by **oren** » Sat Nov 09, 2013 6:33 am

After teaching many weaker players on life and death, I find it a very useful proverb. You don't reduce first, but it is usually the best place to start reading.

John Fairbairn · Post by **John Fairbairn** » Sat Nov 09, 2013 7:15 am

Instead of speaking of "a move that reduces the eyespace", several years ago, I have maybe invented the term "reduction". It is a play of the type of reducing the eyespace. With such a term, efficient language use becomes possible, when discussing life and death situations. E.g., "This reduction kills the group."

As I suspected earlier, you are indeed redefining the meaning of reduction without telling your audience. But that process explains much else. I now understand that you have also redefined 'efficient' to mean 'inefficient'.

When the (bad) proverb says "First reduce, then play on the vital point.", it is weak if the meaning of "reduce" refers to one particular move and place where to reduce. The proverb's meaning is a bit better when "reduce" is understood as a process of reducing the eyespace of an attacked group with several moves from different directions.

It's easy to invent dragons and then claim a reputation for slaying them. You have (as a non-native speaker of English) apparently latched onto a perverted sense of "first" as meaning this is the very first step you take when doing life and death problems. A list-oriented person may think that, but most of us just think of it as implying order only within the sentence: "after" you do that (the hane), you do this. We don't blindly assume hane is always the starting move. Even if you were to have doubts about that, there are plenty of texts that explain the thinking. For example, Kitani's lecture on L&D tells us there are three basic categories (in no special order): those where "width" of eyespace is one thing to concentrate on, the focal point (aka vital point) is another to concentrate on, and a third basic case is where you have to suspect special conditions (ko and seki). And he managed to train a few kiseis and meijins without inventing gibberish.

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 7:40 am

John, the definition I provide is:

"The attacker's reduction decreases the eyespace of the defender's group from the outside."

This need not be called "re-definition", but rather it is a clarification of what some might call obvious. After all, what else would you expect 'reduction' to mean?:)

***

Your description of the proverb is an improvement, which I wish would be used more often. Usually, the proverb is described in a list fashion, see e.g. the Kageyama.

I do not have doubts that there are (relatively few) exceptions of teachers, whose teaching of LD is slightly better. Kitani's belongs to them. Three basic categories is a start, but intermediate and advanced problem solving needs more to overcome the exploding size of the game tree.

***

oren, having just studied hundreds of problems and their solutions, I know that usually the best place to start reading is the one and only obvious move. If there is not exactly one obvious move, then it often is necessary to consider each interesting first move (until some optimal move is found and verified). LD problems can have surprises everywhere, and (without obvious move) a "first consider a reduction" approach is the most probable, but by far not the only approach to a solution to be considered.

oren · Post by **oren** » Sat Nov 09, 2013 7:58 am

Do you think ddk know an obvious move.

I have taught many who do a lot of problems and they play from the inside in games and fail. Start by reducing eyespace from outside is very useful for beginners to know.

RBerenguel · Post by **RBerenguel** » Sat Nov 09, 2013 8:03 am

John Fairbairn wrote: For example, Kitani's lecture on L&D tells us there are three basic categories (in no special order): those where "width" of eyespace is one thing to concentrate on, the focal point (aka vital point) is another to concentrate on, and a third basic case is where you have to suspect special conditions (ko and seki). And he managed to train a few kiseis and meijins without inventing gibberish.

Sorry to derail the thread Robert. John, which lecture is this? You have piqued my curiosity.

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 8:12 am

oren, a move is obvious, if it is obvious for the player doing an LD problem. If there is no move that is obvious to him, then he needs to fall back to checking each interesting move. Stronger players can identify more moves as 'obvious' than DDK can. IOW, there is no attempt to define which move is the obvious move. It is the player's insight or missing insight that there is or is not some obvious move.

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 8:32 am

Maybe a bit of confusion arises, because the context "in life and death situations" has not been clear?

Without more specific context, my general definition of a reduction is:

"A reduction reduces the opponent's eyespace, territory or moyo."

In the more specific context of LD situations, there can be the more specific instance of a definition:

"In a life and death situation, the attacker's reduction decreases the eyespace of the defender's group from the outside."

Similarly, one can specify the instance for the context of territories / moyos:

"With respect to the defender's territory or moyo, the attacker's reduction decreases its size from the outside."

In these definitions, "the attacker's reduction" could be spelled out as "the attacker's reduction move".

I hope that everything is clear now:)

oren · Post by **oren** » Sat Nov 09, 2013 8:37 am

In the case of ddk the obvious move is often wrong. I do think they should first figure out why reducing from outside would not work. Many fall into this trap.

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 10:01 am

Would any DDK miss the obvious move here?

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Click Here To Show Diagram Code: [go]$$B $$ +-------------------+ $$ | . X X . X X X . . | $$ | O X O O O O X O . | $$ | O X O O X X X O . | $$ | O X X . X O O O O | $$ | O O O O O O X X X | $$ | . . . . . O X . X | $$ | . . . . . O X X . | $$ +-------------------+[/go]

Click Here To Show Diagram Code: [go]$$B $$ +---------------+ $$ | . O X . X O . | $$ | X O . X O O X | $$ | X O O O O . X | $$ | X . . , . X . | $$ | . X . X X . . | $$ | . . X . . . . | $$ | . . . . . . . | $$ +---------------+[/go]

RBerenguel · Post by **RBerenguel** » Sat Nov 09, 2013 10:18 am

1: No

2: As black to play, a DDK may wonder ad-nauseam if the group is alive or not after move 1.

3: As white? Absolutely. As black? Unlikely

RobertJasiek · Post by **RobertJasiek** » Sat Nov 09, 2013 10:30 am

Yes. Even a DDK must learn to read when the move is not obvious for him. At least there are a few moves that are obvious. No need to consider reductions then (unless the obvious move is the reduction).

Bonobo · Post by **Bonobo** » Sat Nov 09, 2013 1:33 pm

RobertJasiek wrote:Would any DDK miss the obvious move here?

I’m ~13k, and for me it is clear where to place my stone, never mind the colour, the spots are blinking red, ringing an alarm bell, and hopping up and down, screaming “HERE, HERE”.

Life In 19x19

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