Knotwilg's practice

Bill Spight · **#141**

Ian Butler wrote:

That was over quickly

Only a few days ago I explored the option of cutting like your opponent did at the 3-3 invasion. Don't feel like you can get a real good result, more of a trick move.

It has been played after the O-18 - N-18 exchange.

Uberdude · **#142**

Playing that cutting hane after attach and pull back is an AI joseki: http://www.alphago-games.com/view/event ... /1/move/15 (which has a detailed WeiqiTV video review). The idea is you want white to cut leading to liberty shortages / bad aji so you should hane early because if you do it after then 2nd line hane connect white might not cut but dodge. Here Ke Jie dodged anyway! http://ps.waltheri.net/database/game/76897/. In the British championship I played 2nd line first which was a slight mistake but it ended up reverting because Sam cut when I haned later anyway:

And here I dodged just to annoy Boris: viewtopic.php?f=48&t=13672&p=231966&hilit=boris#p231966

Knotwilg · **#143**

Some time ago Ian asked "what is your weakness". After many games on Foxy I'd say, "picking fights when I'm ahead". I often get an early advantage, so when my opponent goes all out attacking, I engage instead of dodging. So this is now my challenge for the next 5 games: when ahead, reduce risk; offer the opponent to take a small gain and secure the lead.

Knotwilg · **#144**

Knotwilg wrote:

Some time ago Ian asked "what is your weakness". After many games on Foxy I'd say, "picking fights when I'm ahead". I often get an early advantage, so when my opponent goes all out attacking, I engage instead of dodging. So this is now my challenge for the next 5 games: when ahead, reduce risk; offer the opponent to take a small gain and secure the lead.

Well, I won all 5 games. In 2 of them the opponent resigned after the early advantage. In the others I think I fared well in playing solidly and securing the win.

Foxy 3d probably still is below my level. I'll next play a few games as 2d on KGS and review them with LZ to see where I need improvement.

Knotwilg · **#145**

In the light of "modern endgame theory", how does it work in practice?

Here's a game of mine that ended in 2,5 for White (actually the opponent lost on time) but if I play what I think is ideal endgame from 204 onwards, is a half pointer.

I've done my endgame analysis but had to fall back on what I think is deiri - traditional theory.

At 204 there are moves A-H. What's their value?

Knotwilg · **#146**

Click Here To Show Diagram Code: [go]$$ Position at move 204 $$ --------------------------------------- $$ | . . . . h . . . . . . . . . . . . . . | $$ | . . . X . O X O . . . . X O . a . . . | $$ | . . X O O O X O O O O . . . O O X . . | $$ | . . X X O X O O X O X O O O X , X . . | $$ | . . . X X X X X X O X O X X X . . . . | $$ | . . O O O X . g O X X X O . . . X . . | $$ | . . . . X O X X O X O X O O O O X . . | $$ | . O . X f O O O O X . O O X X O O b . | $$ | . X . X O . . . . . O O X . X X O . . | $$ | . X . X e . . . O d O X X X X O O . . | $$ | . X O . O . . . O X X X O . X X X X . | $$ | . X O . O . . O X O . . c . . . X . X | $$ | . . X O . . . O X . O X . O . X O X . | $$ | . X . X O . . O O X . . . . O O O O . | $$ | . O . . . . O O X O O O O O X X X O . | $$ | . . O O O . X O X X O X O X . , . X . | $$ | . X X X O X . O X . X . X X . X X X . | $$ | . O O O X . X X . X X X . O X . . . . | $$ | . . . . . X . . X . . . . . . X . . . | $$ ---------------------------------------[/go]

Knotwilg · **#147**

Lizzie's analysis:

Click Here To Show Diagram Code: [go]$$ Position at move 204 $$ --------------------------------------- $$ | . . . . h . . . . . . . . . . . . . . | $$ | . . . X . O X O . . . . X O . a . . . | $$ | . . X O O O X O O O O . . . O O X . . | $$ | . . X X O X O O X O X O O O X , X . . | $$ | . . . X X X X X X O X O X X X . . . . | $$ | . . O O O X . g O X X X O . . . X . . | $$ | . . . . X O X X O X O X O O O O X . . | $$ | . O . X f O O O O X . O O X X O O b . | $$ | . X . X O . . . . . O O X . X X O . . | $$ | . X . X e . . . O d O X X X X O O . . | $$ | . X O . O . . . O X X X O . X X X X . | $$ | . X O . O . . O X O . . c . . . X . X | $$ | . . X O . . . O X . O X . O . X O X . | $$ | z X . X O . . O O X . . . . O O O O . | $$ | . O . . . . O O X O O O O O X X X O . | $$ | . . O O O x X O X X O X O X . , . X . | $$ | . X X X O X . O X . X . X X . X X X . | $$ | . O O O X . X X . X X X . O X . . . . | $$ | . . . y . X . . X . . . . . . X . . . | $$ ---------------------------------------[/go]

LZ definitely sees A as the biggest move, not only for Black but also for White. The hane to the right of A is also considered sente by LZ, as Black will respond up to S19 but A itself is more clearly sente

So much even that moves like E or F are not sente for Black in the global sense. White will play A in sente and grab a few capital points there.
D is obviously Black sente and as such incidental to the game
F is White sente

LZ agrees that B and C are the next big gote and will play either of them early, but definitely after A
G is on LZ's radar but not as an early move
H is incidental to the game, as it is sente for 0 points and then can make 1 point

In the bottom left corner, there are some border plays I missed

X - White gains a point there and threatens to capture a stone with a ko follower; Black can forestall this, threatening to enter WHite's territory but not in a big way
Y - is bigger than it may seem; if unanswered, Black can force a capture that loses 6 points compared to White playing 2 herself; if answered, White saves 3 of those points, so 2) is a 3 point sente for Black / 6 point gote
Z - if Black plays there, he makes two points; White playing 3 protects some points in the corner AND sets up a throw-in that gets 3 more points

Click Here To Show Diagram Code: [go]$$B Moves 205 to 214 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . O X O . . . . X O 2 1 3 . . | $$ | . . X O O O X O O O O . . . O O X . . | $$ | . . X X O X O O X O X O O O X , X . . | $$ | . . . X X X X X X O X O X X X . . . . | $$ | . . O O O X . . O X X X O . . . X 7 . | $$ | . . . . X O X X O X O X O O O O X 6 . | $$ | . O . X . O O O O X . O O X X O O 8 . | $$ | . X . X O . . . . . O O X . X X O . . | $$ | . X . X . . . . O , O X X X X O O . . | $$ | . X O . O . . . O X X X O . X X X X . | $$ | . X O . O . . O X O . 5 4 . . . X . X | $$ | . . X O . . . O X . O X . O . X O X . | $$ | . X . X O . . O O X . . . . O O O O . | $$ | . O . . . 0 O O X O O O O O X X X O . | $$ | . . O O O 9 X O X X O X O X . , . X . | $$ | . X X X O X . O X . X . X X . X X X . | $$ | . O O O X . X X . X X X . O X . . . . | $$ | . . . . . X . . X . . . . . . X . . . | $$ ---------------------------------------[/go]

In LZ's continuation, :w4:

is sente and so White grabs :w6:

too.

Click Here To Show Diagram Code: [go]$$B Moves 215 to 224 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . O X O . . . . X O O X X . . | $$ | . . X O O O X O O O O . . . O O X . . | $$ | . . X X O X O O X O X O O O X , X . . | $$ | . . . X X X X X X O X O X X X . . . 9 | $$ | . . O O O X . . O X X X O . . . X X 8 | $$ | . . . 3 X O X X O X O X O O O O X O 0 | $$ | . O . X 2 O O O O X . O O X X O O O . | $$ | . X . X O . . . . . O O X . X X O . . | $$ | . X . X 1 4 . . O , O X X X X O O . . | $$ | . X O . O . . . O X X X O . X X X X . | $$ | . X O . O . . O X O . X O . . . X . X | $$ | . . X O . . . O X . O X . O . X O X . | $$ | 7 X . X O . . O O X . . . . O O O O . | $$ | . O . . . O O O X O O O O O X X X O . | $$ | . 6 O O O X X O X X O X O X . , . X . | $$ | . X X X O X . O X . X . X X . X X X . | $$ | . O O O X . X X . X X X . O X . . . . | $$ | . . . 5 . X . . X . . . . . . X . . . | $$ ---------------------------------------[/go]

Both grab central sente, then the Y and Z moves in the corner are executed. Next, White executes the sente follower in the upper right

Click Here To Show Diagram Code: [go]$$B Moves 225 to 233 $$ --------------------------------------- $$ | . . . . 7 . 8 . . . . . . . . a . . . | $$ | . . 5 X 4 O X O . . . . X O O X X . . | $$ | . . X O O O X O O O O . . . O O X . . | $$ | . . X X O X O O X O X O O O X , X . . | $$ | . . . X X X X X X O X O X X X . . 1 X | $$ | . . O O O X 9 6 O X X X O . . b X X O | $$ | . . . X X O X X O X O X O O O O X O O | $$ | . O . X O O O O O X . O O X X O O O . | $$ | . X . X O . . . . . O O X . X X O . . | $$ | . X h X X O . . O i O X X X X O O 3 . | $$ | . X O g O . . . O X X X O . X X X X . | $$ | . X O . O . . O X O . X O . c . X . X | $$ | . . X O . . . O X . O X . O . X O X . | $$ | X X . X O . . O O X . d . . O O O O . | $$ | . O . f . O O O X O O O O O X X X O . | $$ | . O O O O X X O X X O X O X . , . X . | $$ | . X X X O X . O X . X . X X . X X X . | $$ | . O O O X . X X . X X X . O X . . . . | $$ | . . 2 X e X . . X . . . . . . X . . . | $$ ---------------------------------------[/go]

Small endgame remains and the game is very tight

A - 2 gote with some aji for White
B - 1 gote with 1 sente follower for White
C - 1 gote with 3 gote follower for white
D - 1 sente Black
E - ko with ko follower
F - 1 gote with major follower, so probably 1 sente White
G - 1 sente Black
H - 1 sente White
I - 1 sente Black

dfan · **#148**

I have gained a lot of endgame points with Y over the years! Those three stones (after you extend) that are left behind after the 3-3-invasion-double-hane joseki have a lot of subtle uses that players (at least at my level) often undervalue.

Bill Spight · **#149**

Top of the head point. In the last diagram :w4:

should be at 7. Which means that :b3:

should also be at 7.

Edit: My bad. Off the top of my head I thought that the top left was a Black sente, but it is a White sente. See later note.

Knotwilg · **#150**

I took this game as the sample game for "Practical Endgame"

https://senseis.xmp.net/?DieterVerhofst ... calEndgame

Bill, I'm not sure about your analysis. That move seems totally incidental to the game?

Bill Spight · **#151**

Top left play.

My bad. This position is a White sente.

Click Here To Show Diagram Code: [go]$$W White sente $$ ----------------------- $$ | . C 4 . 1 . 3 C . . . $$ | . C C X 2 O B O . . . $$ | . . X O O O B O O O O $$ | . . X X O X O O X O X $$ | . . . X X X X X X O X $$ | . . O O O X . . O X X $$ | . . . . X O X X O X O $$ | . O . X . O O O O X . $$ | . X . X O . . . . . O $$ | . X . X . . . . O . O[/go]

Local result: -2.

Click Here To Show Diagram Code: [go]$$W White's threat $$ ----------------------- $$ | . 6 5 7 1 C C C . . . $$ | . 4 3 B C O B O . . . $$ | . . X O O O B O O O O $$ | . . X X O X O O X O X $$ | . . . X X X X X X O X $$ | . . O O O X . . O X X $$ | . . . . X O X X O X O $$ | . O . X . O O O O X . $$ | . X . X O . . . . . O $$ | . X . X . . . . O . O[/go]

Local result: -10. White gains 8 pts. in 2 net plays.

Click Here To Show Diagram Code: [go]$$B Black reverse sente $$ ----------------------- $$ | . C C C 1 . 2 C . . . $$ | . C . X 3 O B O . . . $$ | . . X O O O B O O O O $$ | . . X X O X O O X O X $$ | . . . X X X X X X O X $$ | . . O O O X . . O X X $$ | . . . . X O X X O X O $$ | . O . X . O O O O X . $$ | . X . X O . . . . . O $$ | . X . X . . . . O . O[/go]

Local result: -1.

The reverse sente gains 1 pt.

----

Edit: Alternate White sente.

Click Here To Show Diagram Code: [go]$$W White sente $$ ----------------------- $$ | . C C . 2 . 3 C . . . $$ | . C 4 X 1 O B O . . . $$ | . . X O O O B O O O O $$ | . . X X O X O O X O X $$ | . . . X X X X X X O X $$ | . . O O O X . . O X X $$ | . . . . X O X X O X O $$ | . O . X . O O O O X . $$ | . X . X O . . . . . O $$ | . X . X . . . . O . O[/go]

Local result: -2.

This way is not as good for White in terms of ko threats.

Knotwilg · **#152**

Thanks Bill!

I saw it as a 1 reverse sente for Black indeed.

With the bad aji Black has in that corner, he'd probably best leave that position alone and for example first secure his second eye, which is also a White sente I believe (1 point threatening 4 more).

So not urgent, on the contrary. Correct?

Bill Spight · **#153**

Knotwilg wrote:

Thanks Bill!

I saw it as a 1 reverse sente for Black indeed.

With the bad aji Black has in that corner, he'd probably best leave that position alone and for example first secure his second eye, which is also a White sente I believe (1 point threatening 4 more).

So not urgent, on the contrary. Correct?

Considering the aji I am not at all sure that those plays are independent. If not, then the calculations are all wrong and the urgency is high. Which is how the humans played it. However, top bots are sensitive to aji and LZ plays them as though they were independent. {shrug}

Knotwilg's practice

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