I have three questions.

1) When should one go for a Ko?

2) How can you tell when something is a Ko threat?

and

3) Why do most DDK players (like me) just fill the Ko when one arises on the board?

Plausible answer of mine for 1.
1 - answer)
I've thought of two reasons why it would be advantageous to fight a Ko:
a) When one is behind on the board, and could conceivably catch up by winning the Ko.
b) To save (or kill) a group that needs to win the Ko to live.
c) When one has more Ko threats than one's opponent.

Are there any other reasons why you'd fight a Ko?

As for 2, other than the obvious ataris (threatening to capture some stones), the obvious saving of stones (threatening to save some stones), and the pushing through gaps in your opponents stones are there any other Ko threats.

And, as for 3, I'm at a loss at why DDKs don't play Kos. Is it because we're scared, lazy (due to lack of reading), or just lack experience?

_________________
My plan to become an SDK is here.

if you want to be a strong go player you must learn to fight ko.
1) i suggest you to learn the calculate the weight of the ko before you start..
if you lose ko...if your opponent lose ko what is the consequence of losing.
2) after that you should count the number of ko threat.
3) finally you should know if you need to fight the ko by counting. avoid ko if you can win without fighting and if you are losing..force ko fight to create more variation.

i hope it helps.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

So, how do you calculate the weight of the Ko?

_________________
My plan to become an SDK is here.

in my opinion it comes out of experience...
if you see all the results and compare...then you can see which picture is better?
that is how i do.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

What happens if you win, versus what happens if you lose. For example, if your opponent risks a big group, and you risk very little, it is called a 'picnic ko' because it's so safe and comfortable for you. Conversely, if you would lose the game if you lose the ko, it may be worth spending a turn to fill in the ko if you have the opportunity.

If it looks like your opponent has a lot of ko threats, you may want to wait, and hope to have more threats later for when you fight the ko. If your opponent spends a turn filling the ko before that, then at least you get sente again. Another thing to know is, in the beginning, there are rarely ko threats worth as much as a ko, so whoever takes the ko will often want to go ahead and fill it in at the first threat.

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Someday I want to be strong enough to earn KGS[-].

The easiest way to improve your ko playing strength is to learn the definitions of internal ko threats vs external ko threats. It will help you in some kos - probably not the majority. It requires no counting.

Below are examples of both. The black group in the upper left has one definite eye. The other potential eye at 'a'. It depends on the ko at D18/D17.
The possible eye at 'a' is a false eye if white wins the ko and permanently occupies D18. Then black dies.
However, if black wins the ko and permanently occupies D18, then 'a' is a real eye and black lives with two eyes.

Click Here To Show Diagram Code

[go]$$c
$$ ---------------------------------------
$$ | . X a X X . . . . . . . . . . . . . . |
$$ | X X X O X O . O . . . . . . . . . . . |
$$ | b O O . O O . O . . . . . . . . . . . |
$$ | c O . O O . . . . , . . . . . , . . . |
$$ | X . . . . . . . . . . . . . . . . . . |
$$ | X X X . . . . . . . . . . . . . . . . |
$$ | X . X . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | X X . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . , . . . . . , . . . . X O e . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

A black stone at 'b' is an internal ko threat. If white does not answer it, then black plays 'c' and can connect to the living black group on the side. Now the ko does not kill black even if white wins it. An internal ko threat is one that fundamentally changes the situation about which the ko is being fought.

A black stone at 'd' is an example of an external ko threat. ( In this instance it is worth an immediate two points, plus some hard-to-evaluate influence, and probably some territory. )

If you have internal ko threats, you don't need to count. They are absolutes. They render the ko irrelevent ( except for the point or two of the ko itself )

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Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

for beginners just learning ko, and identifying ko threats...

I like to think of a good threat as "what would happen if I get to play two moves in a row here" -- because if you make a threat, and your opponent ignores the threat to either take or fill the ko, then you get to play two moves in a row where you threatened.

but also consider if your "two moves in a row" ko threat is large enough to compensate for losing the ko (if your opponent connects or takes the ko)

In general, the weaker a player is, the less comfortable he is with an unsettled or tense situation, and the more he is inclined to resolve it as soon as possible. (This is true in chess as well; it's really hard to leave a position where pawns can capture each other alone for multiple moves.)

A few consequences:
- Players avoid kos - who knows who might win??
- Players thrash around trying to live instead of leaving the situation alone and using it for ko threats
- Players play out local situations to the bitter end instead of leaving them unsettled and coming back to them later when it's more clear what the best continuation would be.

This is not just an issue at the DDK level; players at my 4k level struggle with these prejudices all the time.

ko is verh hard subject to master..
even top professionals make mistake at ko fight everyday.
that is why stronger player always will have advantage over weaker player when it comes to ko fight..

i believe only way to be better at ko fight is to fight ko in actual game.
but try to read all different results and compare and select the best result and play that move.

..... i guess i am kinda drunk now.. i lost my thought..
i will talk more later...

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

Okay, so let me get this straight. Internal ko threats deal with the life and death nature of the group connected to the ko, and External ko threats deal with the areas of the board with groups whose life and death nature is NOT connected to the ko.



Yeah, I've heard that before, and it makes sense. Your reasons also make sense. However, your second reason begs the additional questions.

When is it appropriate to play local situations to the bitter end?

and

When is it appropriate to leave the local situations and come back for ko threats later?

I'm glad that DDKs aren't the only ones who have this issue with kos.

_________________
My plan to become an SDK is here.

Never

If you know you are dead (and you know your opponent knows how to kill you ), every move you make is a wasted ko threat.

Of course, at your level, and at mine, you may not realize you are dead, or you may not trust your opponent to be able to respond to all your threats to live accurately...

When it is the best play.

(I'm sorry, there is no easy answer.)



In general, when it would be sente if there were no ko.

Many players think that a ko threat is a sente move that must be answered, and therefore must be at least as big as the ko. That is incorrect. A play may be a ko threat even if the opponent should ignore it and win the ko. The point is that in that case it is better to have played the ko threat than not to have done so.



Good question.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Almost true. You are being a tad too particular. If kos were fought only over life and death of a group you would have it exactly right. But kos can be fought over other things, such as whether a territory can be invaded or not.
If you generalize your statement to read "Internal ko threats deal with the dispute that is connected to the ko, and External ko threats deal with the areas of the board where the dispute is NOT connected to the ko", then you have it.

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Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

There are different levels of how to approach this question.

Theory:

While this winter I defined what a ko is, the definition problem of what is a ko threat is on a yet higher level of abstraction and will remain unsolved probably for also at least the next few years.

Naive practice:

Bill Spight has given a reasonable answer: "When it would be sente if there were no ko."

Advanced practice:

There are different types of ko threats (more generally: ko threat and answer sequences) and negative ko threats. You find this discussed elsewhere.

In between practice and theory:

A "standard ko threat"
- is a play,
- immediately follows an opposing play that creates a local ko ban for the player,
- does not create a local ko ban, and
- after perfect play continuation lets the score in favour of the opponent with his reply "in" the ko be at most as great as the score in favour of the opponent with his reply "outside" the ko.

Since usually we cannot determine perfect play, reference to it has to be taken as a guideline in practice. I.e., the last condition can be understood more informally as "It is better for the opponent to answer a (real, not fake) ko threat than to play immediately again in the ko because the former is "bigger" (i.e., will lead to the more favourable score) than the latter.".