Discussion about R16,Q16,Q17,R15

Joseki
1

At position R16,Q16,Q17,R15, @BrucePee started the conversation:

Since black is one stone auead, why doesn’t he just start a fight with Q15?

( FYI @yegorist )

2

@Uberdude said:

q15 is possible too, it’s easier if black has the ladders, but still possible without

( FYI @yegorist )

3

@Uberdude said:

R16,Q16,Q17,R15,Q15,P16,R14,S15,R17

( FYI @yegorist )

4

@aesalon said:

I wonder if you can construct a realistic non-Chinese formation where that sequence would be on par with others? Seems very situational. Example in Chinese: Play Go at online-go.com! | OGS

( FYI @yegorist )

5

@gennan said:

Isn’t white’s Q16 attachment already situational (when black already has a stone at L17). Otherwise the attachment gives black a good result.

( FYI @yegorist )

6

@gennan said:

(Source: lecture by InSeong Hwang, from my memory)

( FYI @yegorist )

7

@aesalon said:

I think that is generally true but it will still appear among AI’s choices in a few situations off the top of my head. That fighting sequence on the other hand seems to rely on a Chinese formation.

( FYI @yegorist )

8

@aesalon said:

I wholeheartedly agree it is situational. I would have thus labeled it as GOOD. It seems I tried to and was overruled :wink:

( FYI @yegorist )

9

@Uberdude said:

If there’s no black Chinesey stone on the top side, then even that fighting variation might not happen as white is probably happier to not extend from r14 atari but r17 and capture the q17 stone…

( FYI @yegorist )

10

@Uberdude said:

…because then white has space to extend on the top side if black extends at s18, and that whole sequence is predicated on the ponnuki being cramped by a top side stone.

( FYI @yegorist )

11

@Uberdude said:

R16,Q16,Q17,R15,Q15,P16,R14,R17,S15,S16,R15,Q18,S17,P17,S18,L17

( FYI @yegorist )