Normally in position below it is recommended to make invasion in the point of symmetry in the middle, at "a". Today I played a game against 2d opponent on KGS and I played invasion at "b" instead.

Click Here To Show Diagram Code

[go]$$ Black to invade
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . . . |
$$ . . . . . , O . . |
$$ . . . . . . b . . |
$$ . . . . . . a . . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . . . |
$$ . . . . . , O 4 . |
$$ . . . . . 2 1 . . |
$$ . . . . . . 6 3 . |
$$ . . . . . . . . . |
$$ . . . . . O O 5 . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Black 3 is the tesuji I found, threatening to connect to both top and bottom. Was this play ideal for white?

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . . . |
$$ . . . . . , O O . |
$$ . . . . . O X 2 . |
$$ . . . . . . O X . |
$$ . . . . . 3 1 . . |
$$ . . . . . O O X . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

I sacrificed the invasion stone in order to cut white's groups apart. Game was a resounding success.

I think White's 2nd line descent was very poor. I don't understand what White's trying to achieve. You've made a connection miai and there are no points on the right edge anyway. You could virtually treat the original move as kikashi as White can only capture it in gote.

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . . . |
$$ . . . . a c O . . |
$$ . . . . . 2 1 . . |
$$ . . . . . b . 3 . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

I thinks White must play a-c somewhere. I think "b" is solid if Black can't cut at "c" and it doesn't look like he can.

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . 6 8 . . |
$$ . . . . 7 5 O . . |
$$ . . . . . 2 1 . . |
$$ . . . . . 4 . 3 . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Now Black must connect underneath, giving White a chance to attack in a big scale in the middle, else the following happens:

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . 3 . . |
$$ . . . . . 2 X . . |
$$ . . . . 1 O O 7 . |
$$ . . . . X X O 8 9 |
$$ . . . . . O X 5 . |
$$ . . . . . O 4 X 0 |
$$ . . . . . . . 6 . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Normal play IIRC is:

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . 7 . |
$$ . . . . . 6 O 5 . |
$$ . . . . . 4 3 . . |
$$ . . . . . 2 1 . . |
$$ . . . . . a . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Black gets such a good result here anyway, and the wedge at "a" still has so much aji, that it feels simpler than playing the contact. FWIW, your line transposes very similarly if Black doesn't try the cut:

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . 7 . |
$$ . . . . . 6 O 5 . |
$$ . . . . . 2 1 . . |
$$ . . . . . 4 . 3 . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Now White can make good shape with the atari, and the wedge aji is not there. Maybe this is why the point of symmetry is more normal ?

Either way the shape White left is just too weak, and with Black on both sides, White should be kicking himself for not playing the following:

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . 1 . . |
$$ . . . . . . . . . |
$$ . . . . 2 . O . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Click Here To Show Diagram Code

[go]$$ Black to invade
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . . . |
$$ . . . . . , O . . |
$$ . . . . . . 1 . . |
$$ . . . . . . 2 . . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

FWIW, my first impression is to respond with the clamp, .

Click Here To Show Diagram Code

[go]$$ Black to invade
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . . . |
$$ . . . . . , O . . |
$$ . . . . . 4 1 3 . |
$$ . . . . . . 2 5 . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

This transposes to a possible variation if White responds with .

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

Visualize whirled peas.

Everything with love. Stay safe.

I definitely don't think white will be "kicking" himself for not playing . I think ignoring is a perfectly fine way to play.

I checked a couple of online position-search databases (DailyJoseki.com and eidogo.com). According to DailyJoseki, which uses the GoGoD database, the following position occured 151 times:

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . . . . . |
$$ . . . . . . 1 . . |
$$ . . . . . . . . . |
$$ . . . . a , O . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

The jump to 'a' was played next only 12 times.

However, I wanted to know what occurred specifically when black has a shimari in the top-right corner. So I turned to eidogo.com and searched this position:

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . B . . |
$$ . . . . . . . . . |
$$ . . . . a , O . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Unfortunately, eidogo.com only returned four results, and no games in it's entire database seem to be newer than 2006. However, in none of those four games did white respond to the marked black stone with a jump to 'a' immediately.

In conclusion, I'm not trying to say the one-space jump is a bad move, just that it definitely does not seem like a "must-play" move. To close, here's an example of black jumping into white's framework after white makes the jump to 'a':

_________________
We don't know who we are; we don't know where we are.
Each of us woke up one moment and here we were in the darkness.
We're nameless things with no memory; no knowledge of what went before,
No understanding of what is now, no knowledge of what will be.

Because of this check, White (in this case) will rarely play this Joseki. Instead:

Click Here To Show Diagram Code

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

Thus 'a' doesn't prepare to seperate White, although Black has 'b' now.

Furthermore there is this:

Click Here To Show Diagram Code

[go]$$Wc
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . 0 . . |
$$ . . . . . , X 1 . |
$$ . . . . . 4 3 2 . |
$$ . . . . . . 5 6 . |
$$ . . . . . . 7 8 . |
$$ . . . . . . 9 . . |
$$ . . . . . . . . . |
$$ . . . . . , c . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . a O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . b . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

...whereon White can make a comfortable extension with 'c' after the a-b-exchange. But this gives away quite a lot of secure territory. Depends on the board, I guess.

_________________
My "guide" to become stronger in Go

I don't think this is necessarily convincing evidence, since there may simple be something even more urgent on the board to play instead. It seems pretty certain that the white group will come under attack if he tenukis, it just may be that white is ok with this depending on the surrounding position.

_________________
"There are no limits. There are plateaus, but you must not stay there, you must go beyond them. If it kills you, it kills you. A man must constantly exceed his level." -- Bruce Lee

@Jedo: Which is exactly my point. At any given time there is going to be more than one thing that white wants to do. However, he must prioritize and start with the most important of them. The fact that white so rarely plays the one-space jump (or any other move around this area) immediately after shows the relative importance of playing in this area versus another point on the board.

Also, notice that the invasion is gote for black, and that white gets some influence from the exchange. Black's invasion hardly seems like a guaranteed occurrence, and if black is in no rush to invade then is white really in a rush to defend?

_________________
We don't know who we are; we don't know where we are.
Each of us woke up one moment and here we were in the darkness.
We're nameless things with no memory; no knowledge of what went before,
No understanding of what is now, no knowledge of what will be.

Yeah that's a good point, I guess once again it's an issue of relative sente.

_________________
"There are no limits. There are plateaus, but you must not stay there, you must go beyond them. If it kills you, it kills you. A man must constantly exceed his level." -- Bruce Lee

I agree completely

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . W W . . |
$$ . . . . X X O . . |
$$ . . . . . O B . . |
$$ . . . . . W . B . |
$$ . . . . . . . . . |
$$ . . . . . O O . . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

I think the are very good moves.

Can Black connect at all?

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . W W . . |
$$ . . . . X X O . . |
$$ . . . . . O B b f |
$$ . . . . . W c B e |
$$ . . . . . . d 2 a |
$$ . . . . . O O 1 g |
$$ . . . . . O X e . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Seems to me that B's cutting stone is simply captured in this process (if B plays simply A or D),
while the upper right corner will suffer collateral damage for a bit of black side-endgame on the right.

Hence, B will play B3 , which will most probably tur^n out to be a bad move.

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . W W . . |
$$ . . . . X X O 3 . |
$$ . . . . . O B . . |
$$ . . . . . W . B . |
$$ . . . . . . . 2 . |
$$ . . . . . O O 1 . |
$$ . . . . . O X . . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . a X . . |
$$ . . . . b W W 7 . |
$$ . . . . X X O 3 . |
$$ . . . . . O B 5 . |
$$ . . . . . W 4 B . |
$$ . . . . . . . 2 . |
$$ . . . . . O O 1 . |
$$ . . . . . O X 6 . |
$$ . . . . . , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

Whit must think however how to continue from here.

I added an SGF with some vars.
________________________________________________________________________________


Black's stones are captured - W is connected. Why?
B1 is not good (pushing from behind) and B3 elsewhere could prevent the capture.
__________________________________________________________________________________________________


Of course!
Black played 7 stones, White only 4!
The rest of the board might/will/should look inverse.



What bad can happen?

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . X . |
$$ . . . f . O O X . |
$$ . . . . e O X . . |
$$ . . . d c O B . . |
$$ . . . . 2 1 3 . . |
$$ . . . 4 . O O . . |
$$ . . . . . O X . . |
$$ . . . . p , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

White has strength/influence.
Cut C can be caught in a net.
( or peep P?)

or

Click Here To Show Diagram Code

[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . . . . |
$$ . . . . . , X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . . X . |
$$ . . . f . O O X . |
$$ . . . . e O X 7 . |
$$ . . . d c O B 5 6 |
$$ . . . . 2 1 3 4 . |
$$ . . . . . O O . . |
$$ . . . . . O X 8 . |
$$ . . . . p , X . . |
$$ . . . X . X . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ -------------------[/go]

or P ?
___________________________________________________________________________________________________


For Black the stretch-out A (threatening cut C) is interesting.
White could mak a Zwischenzug D and accept the ponuki, IMO. (if both like to fight)

_________________
Greetings,
Tommie

3dan EGF (AGA no 13477) || Tommie on KGS: 'June'|| DGS: 'Zhi Laohu' 纸老虎 = 'paper tiger' || Senseis : http://senseis.xmp.net/?tderz ||
ENFP (MBTI) - 'Find your own style within the Fundamentals of Go! '

Thanks, Tommie!

Here are a few variations. What do you think?

[sgf-full](;FF[4]GM[1]SZ[19]AP[GOWrite:2.2.21]CA[ISO8859-1]ST[2]AB[qd][oc][pq][qp][qo][nq][qh]PM[2]PB[ ]AW[po][pn][qn][qj]PW[ ]GN[ ]FG[259:]
;B[qk]
;W[ql]
;B[pk]
;W[rk]
(
;B[rj]
;W[ri]
;B[rl]
;W[sj]
;B[qm]
(
;W[pl]
(
;B[pm]
;W[ol]
(
;B[rm]
;W[om]
;B[rn]
;W[oj]
)
(
;B[om]
;W[rm]
;B[rn]
;W[sl]
;B[ro]
;W[nm]
;B[on]
;W[nn]
;B[oo]
;W[no]
;B[op]
;W[nl]
)

)
(
;B[rn]
;W[pm]
;B[rm]
;W[ok]
)

)
(
;W[rm]
;B[pl]
;W[sl]
(
;B[rn]
;W[ql]
)
(
;B[pm]
;W[ro]
)

)

)
(
;B[rl]
;W[rm]
;B[rj]
;W[sl]
)

)[/sgf-full]

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

Visualize whirled peas.

Everything with love. Stay safe.

To write in words, what has been edited in the SGF will not be clear for everyone, I imagine.

The final variation/position of your SGF (at this moment; 2 black stones caught in geta)
does not seem interesting to me,
as W dominates the center, and Black did creepy endgame on the second line (right)
AND furthermore also hurt his upper position (because the 2.-line ponuki is strong).

Cause: the 2nd atari in the variation was unecessary.
If only 1 atari, W cannot capture in geta (as there is the weakness Q10 and W can only attempt lose ladder, resp. trying geta with 3 libs; shown in SGF)

_________________
Greetings,
Tommie

3dan EGF (AGA no 13477) || Tommie on KGS: 'June'|| DGS: 'Zhi Laohu' 纸老虎 = 'paper tiger' || Senseis : http://senseis.xmp.net/?tderz ||
ENFP (MBTI) - 'Find your own style within the Fundamentals of Go! '