Opening for black?

Ian Butler · Post by **Ian Butler** » Sun May 13, 2018 8:34 am

I was brushing up on my joseki a bit and I was wondering if this could be a decent opening strategy for black?
If white approaches the 3-4 stone, black can almost always make it work so that he gains some strength/influence over the left side, where he already has that D10 stone. So that makes is less interesting for white to approach the 3-4, maybe?

Just a thought I had, let me know what you think. Since this is no common opening, there's probably something wrong with it, so I'm interested to know what it is I'm missing

It's close to sanren-sei, so maybe the sanren-sei does the same just a bit better?

And also: Would the opening be better/worse with other white stones, instead of niren-sei?

Also let's call this the Impolite Opening since black obviously didn't open at the upper right corner!

Click Here To Show Diagram Code: [go]$$c Opening for black? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Calvin Clark · Post by **Calvin Clark** » Sun May 13, 2018 9:11 am

The only way to know is to play. Chances are your opponent will play here. What are your thoughts?

Click Here To Show Diagram Code: [go]$$W $$ -------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , 1 . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

You should also minimally prepare against this:

Click Here To Show Diagram Code: [go]$$W $$ -------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 1 . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

And because it's 2018

Click Here To Show Diagram Code: [go]$$W $$ -------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Kirby · Post by **Kirby** » Sun May 13, 2018 9:26 am

I think it's inconsistent. The two star point stones aim for influence that has potential to make a nice shape on the top and bottom sides.

But the territorial 3-4 stone invites white to approach and spoil that influence.

I'd only recommend this opening if you had a special plan for white's approach.

If you're not going for San-ren-sei, the 3-4 stone should emphasize influence. You could even play around like this:

Click Here To Show Diagram Code: [go]$$c Opening for black? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , B . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Bill Spight · Post by **Bill Spight** » Sun May 13, 2018 10:13 am

Ian Butler wrote:I was brushing up on my joseki a bit and I was wondering if this could be a decent opening strategy for black?

This:

Click Here To Show Diagram Code: [go]$$c Opening for black? $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Why not?

If white approaches the 3-4 stone, black can almost always make it work so that he gains some strength/influence over the left side, where he already has that D10 stone. So that makes is less interesting for white to approach the 3-4, maybe?

No. One general rule in the opening is that box shapes are good. So if you have two stones forming one side of a box, you usually want to extend from them to form a triangle, which threatens to add another stone to form a box. In this position Black is threatening to form triangles on both the top and bottom sides, as well as a smaller triangle by enclosing the top left corner. So White will want to approach both left corners to prevent that, although he probably cannot prevent both triangles, by miai.

Another general rule is that the wider open space on the side makes plays there bigger. So White will usually prefer to approach the top left corner than the bottom left corner. BTW, you can see that rule in action in the corresponding position before

at https://alphagoteach.deepmind.com . AlphaGo prefers to enclose the top left corner (top right in that case) or approach White's top corner than to approach White's bottom corner.

That said, I found 8 roughly similar position on Waltheri ( http://ps.waltheri.net ), with 4-4 results. So even if this opening is inferior, it is only a little inferior.

Click Here To Show Diagram Code: [go]$$Bc 2 space high approach $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . a . . . . . . . . . . . . . | $$ | . . X , . 6 . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

White has a nice play at

, or possibly the large knight's approach at "a".

Click Here To Show Diagram Code: [go]$$Bc Pincer $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X , 6 . . 7 . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 9 . 8 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . B . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

invites the two space high pincer. The value of

lies not so much in making territory as in attacking the White stones.

Gomoto · Post by **Gomoto** » Sun May 13, 2018 11:07 am

ELF thinks not:

Tryss · Post by **Tryss** » Sun May 13, 2018 11:43 am

Doesn't ELF consider that Black has 47% winrate on an emptyboard?

For exemple, LeelaZero evaluate the sanrensei about the same as this opening (and its evaluation of this position is the same as in your screenshot).

So, it should be perfectly playable for humans

Gomoto · Post by **Gomoto** » Sun May 13, 2018 12:11 pm

ELF starts with 49.5% for black, 56.5% for white doesn't cut it for me.

Gomoto · Post by **Gomoto** » Sun May 13, 2018 12:13 pm

ELF starts with 49.5% for black, 56.5% for white doesn't cut it for me.

(also have a look here: forum/viewtopic.php?p=231137#p231137)

... and be assured you can feel the 7% difference in winning chance as human quite well over the board.

(@Tryss, thanks for your post, wrong Leela pic updated to Elf pic.)

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