For beginners, one of the very first joseki learned is how to handle a 3-3 invasion under a 4-4 stone. And for the most part you end up with this familiar shape.
$$Bc
$$ . . . . . . . |
$$ . . . . X . . |
$$ . . . . X O . |
$$ . . . . X O . |
$$ . . . X O . . |
$$ . X . X O . . |
$$ . . X O O . . |
$$ . . . . . . . |
$$ --------------+
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[go]$$Bc
$$ . . . . . . . |
$$ . . . . X . . |
$$ . . . . X O . |
$$ . . . . X O . |
$$ . . . X O . . |
$$ . X . X O . . |
$$ . . X O O . . |
$$ . . . . . . . |
$$ --------------+[/go]
There is nothing wrong with the above but you need to be careful that you don't automatically play like this whenever you face a 3-3 invasion.
Now another common situation beginners face is the pincer against the low approach to the 4-4 corner and which is answered with the 3-3 invasion.
$$Bc
$$ . . . . . . . . . |
$$ . . . . . 1 . . . |
$$ . 3 . 2 . . 4 . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . 1 . . . |
$$ . 3 . 2 . . 4 . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
Some people might want to separate the invasion stone from linking with the pincered stone and thus they would choose to block. Still looks good so far.
$$Bc
$$ . . . . . . . . . |
$$ . . . . . 1 . . . |
$$ . 3 . 2 . 5 4 . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . 1 . . . |
$$ . 3 . 2 . 5 4 . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
Now if we follow a common joseki, we'd arrive at this position
$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . O . . |
$$ . . . . . X . . . |
$$ . . . . . X O . . |
$$ . X . O X X O . . |
$$ . . . . X O O . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . O . . |
$$ . . . . . X . . . |
$$ . . . . . X O . . |
$$ . X . O X X O . . |
$$ . . . . X O O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
But some people might think that Black should seek more and try to aim for something like this.
$$Bc
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . X O . |
$$ . . . . . . X O . |
$$ . . . . . X O . . |
$$ . X . O X X O . . |
$$ . . . . X O O . . |
$$ . . . . . . . . . |
$$ ------------------+
- Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . X . . |
$$ . . . . . . X O . |
$$ . . . . . . X O . |
$$ . . . . . X O . . |
$$ . X . O X X O . . |
$$ . . . . X O O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
Doesn't it look like Black could earn a lot more if he played the hane as if it were just the 3-3 invasion without the pincer exchange? So what's wrong with this and why is it not joseki?
The problem is that White will not just easily follow the 3-3 invasion joseki, instead White will answer the hane with a descend.
$$Bc
$$ . . . . . . . . . |
$$ . . . . . . 1 . . |
$$ . . . . . X O . . |
$$ . X . O . X O . . |
$$ . . . . . . 2 . . |
$$ . . . . . . . . . |
$$ ------------------+
Now when Black blocks to prevent linkage, White cuts
[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . 0 X . . |
$$ . . . . . X O . . |
$$ . X . O . X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . 1 . . |
$$ . . . . . X O . . |
$$ . X . O . X O . . |
$$ . . . . . . 2 . . |
$$ . . . . . . . . . |
$$ ------------------+
Now when Black blocks to prevent linkage, White cuts
[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . 0 X . . |
$$ . . . . . X O . . |
$$ . X . O . X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
The usual sequence ends with White having a large corner and Black being a bit overconcentrated.
$$Bc
$$ . . . . . . . . . |
$$ . . . . . 4 6 . . |
$$ . . . . 3 2 X . . |
$$ . . . 5 . X O . . |
$$ . X . O . X O . . |
$$ . . . . . 1 O . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . 4 6 . . |
$$ . . . . 3 2 X . . |
$$ . . . 5 . X O . . |
$$ . X . O . X O . . |
$$ . . . . . 1 O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
But what happens if Black tries to save the r5 stone by extending?
$$Bc
$$ . . . . . . . . . |
$$ . . . . . 5 . . . |
$$ . . . 8 6 4 1 . . |
$$ . . . 7 3 O X . . |
$$ . . . . 2 X O . . |
$$ . X . O . X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . 5 . . . |
$$ . . . 8 6 4 1 . . |
$$ . . . 7 3 O X . . |
$$ . . . . 2 X O . . |
$$ . X . O . X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
Now there are really no good moves for Black afterwards.
$$Bc
$$ . . . . . . . . . |
$$ . . . . . X . . . |
$$ . . . O O O X . . |
$$ . . . X X O X . . |
$$ . . . . O X O . . |
$$ . X 2 O 1 X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+
- Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . X . . . |
$$ . . . O O O X . . |
$$ . . . X X O X . . |
$$ . . . . O X O . . |
$$ . X 2 O 1 X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
$$Bc
$$ . . . . . . . . . |
$$ . . . . . X . . . |
$$ . . . O O O X . . |
$$ . . . X X O X . . |
$$ . . . 1 O X O . . |
$$ . X . O 2 X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . X . . . |
$$ . . . O O O X . . |
$$ . . . X X O X . . |
$$ . . . 1 O X O . . |
$$ . X . O 2 X O . . |
$$ . . . . . X O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
$$Bc
$$ . . . . . . . . . |
$$ . . . . . X . . . |
$$ . . . O O O X . . |
$$ . . . X X O X . . |
$$ . . . . O X O . . |
$$ . X . O . X O . . |
$$ . . . 1 2 X O . . |
$$ . . . . . . . . . |
$$ ------------------+
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[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . X . . . |
$$ . . . O O O X . . |
$$ . . . X X O X . . |
$$ . . . . O X O . . |
$$ . X . O . X O . . |
$$ . . . 1 2 X O . . |
$$ . . . . . . . . . |
$$ ------------------+[/go]
So remember not to confuse the 3-3 invasion with the pincered 3-3 invasion and watch out for that hane.
From a recent game of mine, I was able to recognize the transposition of the pincered 3-3 invasion that was answered by a hane. The game ended quickly with my opponent resigning after I punished his poor moves. Enjoy.
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.50]TM[60]OT[3x10 byo-yomi]
PW[nosmo]PB[tchan001]WR[4k]BR[5k]DT[2012-06-07]PC[The KGS Go Server at
http://www.gokgs.com/]RE[B+Resign]
;B[pd]BL[58.531]
;W[dp]WL[52.316]
;B[fq]BL[55.502]
;W[iq]WL[46.914]
;B[cq]BL[50.599]
;W[dq]WL[44.59]
;B[cp]BL[48.13]
;W[dr]WL[42.962]
;B[do]BL[45.246]
;W[co]WL[41.238]
;B[cr]BL[41.13]
;W[cn]WL[37.168]
;B[ep]BL[38.437]
;W[eo]WL[35.252]
;B[dn]BL[36.913]
;W[fo]WL[33.27]
;B[dm]BL[31.677]
;W[fr]WL[30.552]
;B[er]BL[29.011])