It is currently Mon Apr 22, 2019 3:07 pm

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 381 posts ]  Go to page Previous  1 ... 15, 16, 17, 18, 19, 20  Next
Author Message
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #341 Posted: Sun Feb 03, 2019 2:04 pm 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Kisei game 3, can you find Iyama's 42% mistake and Yamashita's 44% return of the favour; Iyama (white) won in the end. LZ's suggested move is the one I expected watching the game and its analysis appears sound to me. Is it missing something, or did the players really make such a big mistake?



Attachments:
Iyama vs Yamashita Kisei 2019 game 3.sgf [1.87 KiB]
Downloaded 984 times
Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #342 Posted: Thu Feb 07, 2019 4:55 pm 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Iyama has got off to a bad start in the Meijin league, so what may have been assumed as a foregone conclusion that he would top the league to challenge Cho U to regain his title may not be so certain. He started off with a win against Mutsuura Yuta 7d, but then lost to Suzuki Shinji 7d (who? you may ask) by half a point. And just today he lost to prodigal youngster Shibano Toramaru 7d by 1.5 so he's 1-2 so far, with 5 games left.

Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #343 Posted: Fri Feb 08, 2019 6:17 am 
Lives with ko

Posts: 205
Liked others: 41
Was liked: 62
KGS: lepore
You can't leave us hanging... What was the 42% mistake?

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #344 Posted: Sat Feb 09, 2019 9:35 am 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
mhlepore wrote:
You can't leave us hanging... What was the 42% mistake?


Here is the position after move 189. White's stick on row 8 has just finished hassling the black group above and the fight resumed at the bottom left corner. White can push and cut with a-c to capture the cutting stones (each has 3 liberties but black needs to defend the g5 stones so white goes first), but would also like to kill the corner too if possible. LZ 203 says white is at 84%.
Click Here To Show Diagram Code
[go]$$Bc Iyama (white) vs Yamashita, White 84%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . . . . . . . X O . X O O . . . |
$$ | . X O X X b c . . . X O . X O X . . . |
$$ | . . X O X a X . . . X X . X O . . . . |
$$ | . . X O O O X . . , . . . . O , . . . |
$$ | . . X O . X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


First, what if white simply goes for the cut and capture. If white 7 takes a liberty black can connect under in sente and gets to play an important move like r4 next. White ends at 22%.
Click Here To Show Diagram Code
[go]$$Wc Direct cut. 22%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O 7 9 . 5 . . . X O . X O O . . . |
$$ | . X O X X 2 3 4 . . X O . X O X . . . |
$$ | . . X O X 1 X . . . X X . X O . . . . |
$$ | . . X O O O X . 6 , . . . . O , . . . |
$$ | . . X O . X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . . 0 8 . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Instead of 7 white can put in the sente hane in the corner to prevent black's connection, but then black can make a comb group to live in the corner. White 40%.
Click Here To Show Diagram Code
[go]$$Wcm7 No connection, but a comb life. 40%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O 3 5 . O . . . X O . X O O . . . |
$$ | 6 X O X X X O X . . X O . X O X . . . |
$$ | . . X O X O X . . . X X . X O . . . . |
$$ | . . X O O O X . X , . . . . O , . . . |
$$ | . . X O 4 X O O . . . . . . . X . . . |
$$ | 2 X O O X . X . . . . . . . . . . . . |
$$ | . 1 . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Starting with the hane in the corner seems pretty natural to me (and is the correct move says LZ), those white stones are weaker than the wall above so it makes sense to play from that direction, and that hane can often gain you a liberty in a semeai. If black extends with 2 (not best) to make the possibility of a comb group life, white captures a stone with b5 (not best), black ataris with b4 (not best) then white has, in sente, reduced the corner to one eye and got the b1 hane. White up to 96% with black's cooperation.
Click Here To Show Diagram Code
[go]$$Wc Sente moves on corner before cut. 96%.
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . . . . . . . X O . X O O . . . |
$$ | 5 X O X X . . . . . X O . X O X . . . |
$$ | . 3 X O X . X . . . X X . X O . . . . |
$$ | 6 4 X O O O X . . , . . . . O , . . . |
$$ | . . X O . X O O . . . . . . . X . . . |
$$ | 2 X O O X . X . . . . . . . . . . . . |
$$ | . 1 . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Note that 4 above is a mistake, it's better at 6, then white pushes and captures a stone and black gets to defend at f5 and the corner will be a ko. So 3 was also a mistake, it should be at the vital point of 6 too and white is then successful in turning the black corner into 1 eye in sente as before and f5 push and cut. So 2 was also a mistake, see later.

So next white pushes and cuts, and that handy b1 hane means black can no longer connect under in sente, only gote. A big difference.
Click Here To Show Diagram Code
[go]$$Wcm7 Gote connection under. 96%.
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . 9 7 5 . . . X O . X O O . . . |
$$ | O . O X X 2 3 4 . . X O . X O X . . . |
$$ | . O X O X 1 X . . . X X . X O . . . . |
$$ | X X X O O O X . 6 , . . . . O , . . . |
$$ | . . X O . X O O . . . . . . . X . . . |
$$ | X X O O X . X . . . . . . . . . . . . |
$$ | 0 O . 8 . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


So if white hanes in the corner it's better for black to make the hanging connection. Now if white wants to reduce it to 1 eye (best) its gote instead of sente like it was with the descent. If black f5 white can tenuki as the corner is still a ko, so black probably plays in lower right.
Click Here To Show Diagram Code
[go]$$Wc Hanging. 85%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . . . . . . . X O . X O O . . . |
$$ | 5 . O X X . . . . . X O . X O X . . . |
$$ | . 3 X O X . X . . . X X . X O . . . . |
$$ | . 4 X O O O X . . , . . . . O , . . . |
$$ | 2 . X O . X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . 1 . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


If instead of 3 above white pushes and cuts then black can sort-of live in the corner next (thought lower right may be bigger).
Click Here To Show Diagram Code
[go]$$Wc Hanging then cut. 76%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . . 9 7 . . . X O . X O O . . . |
$$ | . X O X X 4 5 6 . . X O . X O X . . . |
$$ | . . X O X 3 X . . . X X . X O . . . . |
$$ | . . X O O O X . 8 , . . . . O , . . . |
$$ | 2 . X O 0 X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . 1 . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

13 doesn't work because black can connect under with 16, and although there is a ko at a2 black winning it is atari so nigh on impossible for white to fight.
Click Here To Show Diagram Code
[go]$$Wcm11 Hanging then cut contd. 76%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | 6 O O . 1 O O . . . X O . X O O . . . |
$$ | 2 X O X X X O X . . X O . X O X . . . |
$$ | . 4 X O X O X . . . X X . X O . . . . |
$$ | 5 3 X O O O X . X , . . . . O , . . . |
$$ | X . X O X X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . O . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


So that's what white should do. But Iyama didn't hane in the corner but just captured the outside stone directly. LZ says this lost 42%, white down from 85 to 43%.
Click Here To Show Diagram Code
[go]$$Wc Capture a stone. 43%
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . . . . . . . X O . X O O . . . |
$$ | 3 . O X X . . . . . X O . X O X . . . |
$$ | . 1 X O X . X . . . X X . X O . . . . |
$$ | . 2 X O O O X . . , . . . . O , . . . |
$$ | . . X O . X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


But this is only if black descends at the vital point in the corner. White can then push and cut as before, but black connects underneath in sente and can move to the lower right. Admittedly black doesn't actually connect to an alive group as he can't get e3 too and LZ might throw away the whole group later in a trade for p4 group later... LZ gives black 52% now.
Click Here To Show Diagram Code
[go]$$Bcm4 Descend, connect under, 48%.
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . b 0 6 . . . X O . X O O . . . |
$$ | O . O X X 3 4 5 . . X O . X O X . . . |
$$ | . O X O X 2 X . . . X X . X O . . . . |
$$ | 8 X X O O O X . 7 , . . . . O , . . . |
$$ | . 9 X O . X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . 1 . a . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


But instead Yamashite played the a4 decent to prevent that atari, -47% says LZ, but then Iyama got to hane in the corner and it ends up sort of like if white played the hane first. If black plays a2 white can just push and cut and black only has the pathetic gote connection like before, so black defended f5 and the corner will be a ko, but white gets sente and is at 91%.

Click Here To Show Diagram Code
[go]$$Bcm4 Yamashita's counter-mistake. White 91%.
$$ ---------------------------------------
$$ | . . . . . . O . O X X . . . . . . . . |
$$ | . O X X . X O O O O X X X X X . O . . |
$$ | . . O X . X X O O X X O O O . X O . . |
$$ | . . O O X . . . O O X . X O X X O . . |
$$ | . . . . . X X X X O X X X X O X O . . |
$$ | . . O . . O . O X O O O X X O X X O . |
$$ | . O . . . O . O O X . O O O O X X O . |
$$ | . X O O . . . . . X . O . O O X O . . |
$$ | X . X . X . . X O . X X O O X O O . . |
$$ | . . . X . . X . . , X O X O X X . . . |
$$ | . X X O X X O X X X . O X X . X . . . |
$$ | . . O O O O O O O O O O . X X . . . . |
$$ | . O O . . . . . . . X O . X O O . . . |
$$ | O . O X X . . . . . X O . X O X . . . |
$$ | . O X O X 3 X . . . X X . X O . . . . |
$$ | 1 X X O O O X . . , . . . . O , . . . |
$$ | . . X O . X O O . . . . . . . X . . . |
$$ | . X O O X . X . . . . . . . . . . . . |
$$ | . 2 . . . X . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


So is there something wrong in this analysis, a move LZ overlooked or dubious judgement? I don't think Iyama could have been scared of the ko in LZ's correct answer, seeing as he went for a ko in the game anyway.


This post by Uberdude was liked by 4 people: Elom, mhlepore, sorin, Waylon
Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #345 Posted: Sat Feb 09, 2019 12:22 pm 
Lives with ko

Posts: 205
Liked others: 41
Was liked: 62
KGS: lepore
Ah very cool - thanks Uberdude. There was a messy fight right from the start so I really had no idea of the goof was earlier or not.

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #346 Posted: Sat Feb 09, 2019 1:10 pm 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
LZ thought there were some mistakes in the early fights around 10%, but it's quite rare to have almost 50% ones in pro games.

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #347 Posted: Thu Feb 14, 2019 1:58 am 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Iyama beat Yamashita in the 4th Kisei game to take a 3-1 lead.

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #348 Posted: Thu Feb 28, 2019 7:11 am 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Yamashita faced kadoban in the 5th game, and after the first days' play (just 49 moves) bots had Iyama with a nice lead of >70% depending which one you asked. But Iyama made a critical mistake in the middlegame (solid extend instead of knight move) which meant Yamashita got a nice squeeze to turn the game around and a big ko trade later couldn't change the result. so Iyama leads 3-2 now.


This post by Uberdude was liked by: ez4u
Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #349 Posted: Thu Feb 28, 2019 9:01 am 
Lives with ko

Posts: 295
Liked others: 241
Was liked: 145
Uberdude wrote:
Yamashita faced kadoban in the 5th game, and after the first days' play (just 49 moves) bots had Iyama with a nice lead of >70% depending which one you asked. But Iyama made a critical mistake in the middlegame (solid extend instead of knight move) which meant Yamashita got a nice squeeze to turn the game around and a big ko trade later couldn't change the result. so Iyama leads 3-2 now.


Don't you mean it is 4-1 now and the title match is over? :-)

_________________
Sorin - 361points.com

Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #350 Posted: Thu Feb 28, 2019 9:42 am 
Beginner

Posts: 3
Liked others: 0
Was liked: 2
Rank: 4k
OGS: DoubleSente
I read Uberdude as saying that Yamashita took a lead and Iyama was unable to take the game back. In that case, Iyama lost game 5, and the series is now 3-2.

Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #351 Posted: Thu Feb 28, 2019 9:50 am 
Lives with ko

Posts: 295
Liked others: 241
Was liked: 145
DoubleSente wrote:
I read Uberdude as saying that Yamashita took a lead and Iyama was unable to take the game back. In that case, Iyama lost game 5, and the series is now 3-2.


Oh, so sorry - I followed this game with swapped colors in my mind!!
I was feeling very sorry for Yamashita blowing the game after such a strong opening, now I need to revise my feelings :-)

_________________
Sorin - 361points.com

Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #352 Posted: Thu Feb 28, 2019 10:30 am 
Lives with ko

Posts: 295
Liked others: 241
Was liked: 145
sorin wrote:
DoubleSente wrote:
I read Uberdude as saying that Yamashita took a lead and Iyama was unable to take the game back. In that case, Iyama lost game 5, and the series is now 3-2.


Oh, so sorry - I followed this game with swapped colors in my mind!!
I was feeling very sorry for Yamashita blowing the game after such a strong opening, now I need to revise my feelings :-)


My revised feelings: Yamashita masterfully turned the game around and got a well deserved win!

I am not necessarily a big fan of Yamashita, but I think Iyama won enough titles already, and it is time for him to pass the baton back to the older generation. :-)

_________________
Sorin - 361points.com

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #353 Posted: Thu Feb 28, 2019 2:51 pm 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
sorin wrote:
Oh, so sorry - I followed this game with swapped colors in my mind!!

Couldn't you tell black was Yamashita from the unconventional high move 7? ;-)

Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #354 Posted: Thu Feb 28, 2019 5:00 pm 
Lives with ko

Posts: 295
Liked others: 241
Was liked: 145
Uberdude wrote:
sorin wrote:
Oh, so sorry - I followed this game with swapped colors in my mind!!

Couldn't you tell black was Yamashita from the unconventional high move 7? ;-)


Both black 7 and 9 seemed unconventionally high indeed, I thought Iyama is so relaxed he can afford to play around and experiment a bit :-)

_________________
Sorin - 361points.com

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #355 Posted: Tue Mar 05, 2019 9:16 am 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Iyama beat Murakawa Daisuke in the first game of the Judan title match today in a pretty convincing fashion. Next up: another chance to win the Kisei vs Yamashita with 6th game on 7th/8th.

Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #356 Posted: Wed Mar 06, 2019 9:16 pm 
Lives with ko

Posts: 295
Liked others: 241
Was liked: 145
Is this going to be Yamashita's losing move, so early at the beginning of day 1?
He played atari and lost 10% right there, and it seems to go downhill from there for him. Maybe too early to say?


Attachments:
iyama_yamashita_kisei_2019_game6.PNG
iyama_yamashita_kisei_2019_game6.PNG [ 789.1 KiB | Viewed 797 times ]

_________________
Sorin - 361points.com
Top
 Profile  
 
Offline
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #357 Posted: Thu Mar 07, 2019 1:03 am 
Dies with sente

Posts: 94
Liked others: 0
Was liked: 8
Quick analyse by lizzie with leelazero 201, black(iyama) is leading, around 63%.

Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #358 Posted: Thu Mar 07, 2019 3:49 am 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
sorin, rather than taking the 40.4 winrate from only 1.8k playouts I'd suggest playing that atari and giving plenty of playouts for a more accurate assessment (particularly as a ko so LZ needs playouts to get through the ko and judge outcome of trades). Elf v2 thought it was a 30% mistake, and the bot they use on Yike 鹰眼 "Hawkeye" gave a similar 45 -> 18% white winrate judgement. Having said that Yamashita won the previous game from a position the bots judged as similarly bad, though there is the question whether this position has a similar scope for a human like Iyama to mess up.

Going back a few moves, all those bots slightly disliked Yamashita's attachment on the shimari, Elf suggesting this very nice nozomi (a shape I've noticed many bots like and I've been trying to promote up my policy network recently, see https://lifein19x19.com/forum/viewtopic ... 23#p227323), attach a crosscut combo. This is too good for white who bullies black into overconcentration whilst making good outside shape, so 4 should wedge but white is still good.

Click Here To Show Diagram Code
[go]$$W
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . O . X . . . O . 3 4 . . 2 . . . |
$$ | . . . . O X . . . . . X 5 . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


This post by Uberdude was liked by 2 people: Bill Spight, dsatkas
Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #359 Posted: Fri Mar 08, 2019 4:22 am 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Gosh, I just checked the game and Yamashita pulled off another reversal from a dismal position (the Yike bot had Yamashita down at 5%). Iyama had 2 weak groups which he should have been able to settle by exploiting the bad aji in Yamashita's attacks and keeping miai for safety, but one little inaccuracy (move 199*) and the group died in ko. Usually it's Yamashita making mistakes vs Iyama in overtime. 3-3 now, decider is on 14-15 March. This would be quite the comeback for Yamashita if he can pull it off, not just from game scores but the losing positions he is winning from when facing kadoban.



* Yike bot said that's where the turning point was, I had a little explore with LZ on low playouts and can see some variations in which blocking from above instead is better because black can force with f11 and h10 causing some shortage of liberties aji in the bamboo joint giving connection aji through e11, though the a12 placement is sometimes a surprise so more thorough analysis needed to conclude black would indeed have survived blocking that way.


This post by Uberdude was liked by: sorin
Top
 Profile  
 
Online
 Post subject: Re: Following Iyama Yuta (no world ranking discussions)
Post #360 Posted: Fri Mar 08, 2019 12:55 pm 
Judan

Posts: 5693
Location: Cambridge, UK
Liked others: 321
Was liked: 3010
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Here's my analysis with LZ 207 about why block other side for 199 was better. Conclusion, it is: having the stone at g13 comes in very useful 40 moves later when black wants to counterattack against white's middle group in a semeai he can then win by 1 liberty, or creating the shortage of liberties in the e10 bamboo combo-ing with e11. There are some lines where white does kill the left group but that involves ignoring a move in the middle so black captures a bunch of stones there in sente and wins anyway. The intuition of these bots to see block above better in just hundreds of playouts (<1 second) when it depends on ~40 move sequences of delicate use of aji is impressive. I expect Iyama could do it too if he had enough time and concentration though.



Attachments:
Iyama Yamashita Kisei 2019 g6.sgf [19.7 KiB]
Downloaded 185 times

This post by Uberdude was liked by 3 people: Bill Spight, dust, sorin
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 381 posts ]  Go to page Previous  1 ... 15, 16, 17, 18, 19, 20  Next

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: Uberdude and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group